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IT threat evolution Q2 2017

Tue, 08/15/2017 - 05:00

Targeted attacks and malware campaigns Back to the future:  looking for a link between old and new APTs

This year’s Security Analyst Summit (SAS) included interesting research findings on several targeted attack campaigns.  For example, researchers from Kaspersky Lab and King’s College London presented their findings on a possible link between Moonlight Maze, a 20 year old cyber-espionage attack that targeted the Pentagon, NASA and others, and Turla – a very modern APT  group.

Contemporary reports on Moonlight Maze show how, starting from 1996, US military and government networks, as well as universities, research institutions and even the Department of Energy, began detecting breaches in their systems.   The FBI and the Department of Defense launched a massive investigation in 1998.  However, although the story became public the following year, much of the evidence has remained classified, leaving the details of Moonlight Maze shrouded in myth and secrecy.  Nevertheless, over the years several investigators have stated that Moonlight Maze evolved into Turla.

In 2016, while researching his book Rise of the Machines, Thomas Rid of Kings College London tracked down a former system administrator whose organisation’s server had been hijacked as a proxy by the Moonlight Maze attackers.  This server, ‘HRTest’, had been used to launch attacks on the US.  The now-retired IT professional had kept the original server and copies of everything relating to the attacks, and handed it to Kings College and Kaspersky Lab for further analysis.  Kaspersky Lab researchers, Juan Andres Guerrero-Saade and Costin Raiu, together with Thomas Rid and Danny Moore from Kings College, spent nine months undertaking a detailed technical analysis of these samples.  They reconstructed the attackers’ operations, tools, and techniques, and conducted a parallel investigation to see if they could prove the claimed connection with Turla.

Moonlight Maze was an open-source Unix-based attack targeting Solaris systems, and the findings show that it made use of a backdoor based on LOKI2 (a program released in 1996 that enables users to extract data via covert channels).  This led the researchers to take a second look at some rare Linux samples used by Turla that Kaspersky Lab had discovered in 2014. These samples, named Penguin Turla, are also based on LOKI2.  Further, the re-analysis showed that all of them use code created between 1999 and 2004.

Remarkably, we’re still seeing attacks that use this code.  It was seen in the wild in 2011 in an attack on defence contractor Ruag in Switzerland that has been attributed to Turla.  Then, in March 2017, Kaspersky Lab researchers discovered a new sample of the Penguin Turla backdoor submitted from a system in Germany.  It is possible that Turla uses the old code for attacks on highly secure victims that might be harder to breach using its more standard Windows toolset.

The newly unearthed Moonlight Maze samples reveal many fascinating details about how the attacks were conducted using a complex network of proxies, and the high level of skills and tools used by the attackers.

So did Moonlight Maze evolve into Turla?  It is not possible to say at this time.  The next step would focus on a little known operation called ‘Storm Cloud:  the evolved toolkit used by the Moonlight Maze operators once the initial intrusions became public in 1999.  The story of Storm Cloud leaked out in 2003 with little fanfare.  However, a few prescient details led us to believe that this intrusion set might give a more definitive answer.

You can find details of the research here.

Lazarus uncovered

In February 2016 a group of hackers (unidentified at that time) attempted to steal $851 million – and succeeded in transferring $81 million from the Central Bank of Bangladesh – in what is considered to be the largest and most successful cyber-heist ever.  Research by Kaspersky Lab and others revealed that the attacks were almost certainly conducted by Lazarus, a notorious cyber-espionage and sabotage group – responsible for the attack on Sony Pictures in 2014, as well attacks on manufacturing companies, media and financial institutions in at least 18 countries around the world since 2009.

Based on our investigations into attacks by the group on financial institutions in South East Asia and Europe, we have been able to provide an insight into the modus operandi of the Lazarus group.

Typically, the initial compromise occurs when a single system within a bank is breached, either by compromising a corporate server or by means of a watering-hole attack – that is, by placing exploit code on a legitimate web site visited by staff at the target institution.  Then the attackers move to other hosts within the organisation and plant a rudimentary backdoor on infected computers.  The group then spends time (days or even weeks) identifying valuable resources within the organisation.  Finally the attackers deploy special malware designed to bypass internal security features and issue rogue banking transactions.

The Lazarus group operates across the globe:  we have found infiltration tools used by Lazarus in multiple countries in the last year or so.

The Lazarus group is very large and has historically focused mainly on cyber-espionage and cyber-sabotage activities.  The group’s interest in financial gain is relatively new and it seems as though a different team within Lazarus is responsible for the generation of illegal profits:  we have dubbed this team Bluenoroff.  So far, we have seen four main types of target:  financial institutions, casinos, companies developing financial trade software and those in the crypto-currency business.

One of the most notable Bluenoroff campaigns was its attacks on financial institutions in Poland.  The attackers were able to compromise a government web site that is frequently accessed by many financial institutions – making it a particularly powerful attack vector.

The Lazarus group goes to great lengths to cover its tracks.  However, one of our research partners made an interesting discovery when completing a forensic analysis of a Command-and-Control (C2) server in Europe that was used by the group.  Based on the forensic analysis report, it was apparent that the attacker connected to the server via Terminal Services and manually installed an Apache Tomcat server using a local browser, configured it with Java Server Pages and uploaded the JSP script for the C2.  Once the server was ready, the attacker started testing it, first with a browser, then by running test instances of their backdoor.  The operator used multiple IPs – from France to Korea, connecting via proxies and VPN servers. However, one short connection was made from a very unusual IP range, which originates in North Korea.  The operator also installed off-the-shelf crypto-currency mining software that should generate Monero crypto-coins:  this software consumed system resources so intensely that the system became unresponsive and froze.  This could be the reason why it was not properly cleaned, and the server logs were preserved.  Of course, while the link to North Korea is interesting, this doesn’t mean we can conclude that North Korea is behind all the Bluenoroff attacks:  someone in North Korea could have accidentally visited the C2 server, or it could be a deliberate false flag operation.

Lazarus is not just another APT group.  The scale of the Lazarus group’s operations is shocking:  it appears that Lazarus operates a malware factory, generating new tools as old ones are ‘burned’.  The group uses various code obfuscation techniques, re-writes its own algorithms, applies commercial software protectors, and uses its own and underground packers.  Typically, the group pushes rudimentary backdoors during the first stage of infection – ‘burning’ these doesn’t affect the group too much.   However, if the first stage backdoor reports an interesting infection they start deploying more advanced code, carefully protecting it from accidental detection on disk:  the code is wrapped into a DLL loader or stored in an encrypted container, or maybe hidden in a binary encrypted registry value.  This usually comes with an installer that only the attackers can use, because they password protect it.  This guarantees that automated systems – be it a public sandbox or a researcher’s environment – will never see the real payload.  This level of sophistication is something that is not generally found in the cybercriminal world and requires strict organisation and control at all stages of operation.  It also explains Lazarus branching out into operations to general illegal profits – operations of this kind require lots of money.

The best defence against targeted attacks is a multi-layered approach that combines traditional anti-malware technologies with patch management, host intrusion detection and a default-deny whitelisting strategy.  According to a study by the Australian Signals Directorate, 85 per cent of targeted attacks analysed can be stopped by employing four simple mitigation strategies:  application whitelisting, updating applications, updating operating systems and restricting administrative privileges.

You can find our report on the activities of the Lazarus group here.

Beating the bank

At this year’s Security Analyst Summit two of our researchers, Sergey Golovanov and Igor Soumenkov, discussed three cases where cybercriminals had stolen money from ATMs.

The first, ATMitch, involved compromising the bank’s infrastructure in order to controlling the operation of the ATM remotely.  The attackers exploited an unpatched vulnerability to penetrate the target bank’s servers.  They used open source code and publicly available tools to infect computers in the bank.  However, the malware they created resided in memory only, not on the hard drives, and almost all traces of the malware were removed when the computer was re-booted.  Following the infection, the attackers established a connection to their C2 server, allowing them to remotely install malware on the ATMs.  Since this looked like a legitimate update, it didn’t trigger any alerts at the bank.  Once installed, the malware looked for the file ‘command.txt’ – this contains the single-character commands that control the ATM.  The malware first issues a command to find out how much money is in the ATM, then issues a further command to dispense money – collected by a money mule waiting at the ATM.  After this, the malware writes all the information about the operation into the log file and wipes ‘command.txt’ clean.

What alerted bank staff to the malware was a single file called ‘kl.txt’.  Thinking that this might have something to do with Kaspersky Lab, the bank called us and asked us to investigate.  We created a YARA rule to search our systems for this file and discovered that we had been seen it twice – once in Russia and once in Kazakhstan.  This enabled us to reverse engineer the malware and understand how the attack works.

One of the other bank attacks also started with a request from the bank.  Money was missing, but the ATM logs were clear and the criminals had taped over the CCTV camera, so that there was no recording of the attack.  The bank delivered the ATM to our office and, after disassembling it, we discovered that there was a Bluetooth adaptor connected to the ATM’s USB hub.  The criminals had installed a Bluetooth adaptor on the ATM and had waited three months for the log to clear.  Then they returned to the ATM, covered the security cameras and used a Bluetooth keyboard to re-boot the ATM in service mode and emptied the dispenser.

Another attack, which, like those mentioned above, started with a bank asking us to investigate an ATM theft, turned out to be much cruder in its approach.  We found a hole, approximately 4cm in diameter, drilled near the PIN pad.  Not long after, we learned of similar attacks in Russia and Europe.  When police caught a suspect with a laptop and some wiring, things became clearer.  We disassembled the ATM to try to find out what the attacker could be trying to access from the hole.  What we found was a 10-PIN header, connected to a bus that connects all of the ATMs components and weak encryption that could be broken very quickly.  Any single part of the ATM could be used to control all the others; and since there was no authentication between the parts, any one of them could be replaced without the others realising.  It cost us around $15 and some time to create a simple circuit board that could control the ATM once we connected it to the serial bus, including dispensing money.

Fixing the problem, as our researchers highlighted, isn’t straightforward.  Patching requires a hardware update and can’t be done remotely:  a technician must visit all the affected ATMs to install it.

You can read more about these incidents here.

Meet the Lamberts

In April, we published a report on an advanced threat actor that can be compared with Duqu, Equation, Regin or ProjectSauron in terms of its complexity.  This group, which we call ‘The Lamberts’ (but which is also known as ‘Longhorn’) first came to the attention of the security community in 2014, when researchers from FireEye discovered an attack using a zero-day vulnerability (CVE-2014-4148).  This attack used malware that we call ‘Black Lambert’ to target a high profile organisation in Europe.

The group has developed and used sophisticated attack tools – including network-driven backdoors, several generations of modular backdoors, harvesting tools, and wipers – against its victims since at least 2008.  The latest samples were created in 2016.  There are currently known versions for Windows and OS X.  However, given the complexity of these projects and the existence of an implant for OS X, we think that it is highly possible that other Lamberts exist for other platforms, such as Linux.

White Lambert runs in kernel mode and intercepts network traffic on infected machines.  It decrypts packets crafted in a special format to extract instructions.  We named these passive backdoors ‘White Lambert’ to contrast with the active ‘Black Lambert’ implants.

We subsequently came by another generation of malware that we called ‘Blue Lambert’.

One of these samples is interesting because it appears to have been used as second stage malware in a high profile attack that involved the Black Lambert malware.

The family of samples called ‘Green Lambert’ is a lighter, more reliable, but older version of Blue Lambert.  Interestingly, while most Blue Lambert variants have version numbers in the range of 2.x, Green Lambert mostly includes 3.x versions.  This stands in contrast to the data gathered from export timestamps and C2 domain activity that points to Green Lambert being considerably older than Blue Lambert.  Perhaps both Blue and Green versions were developed in parallel by two different teams working under the same umbrella, as normal software version iterations, with one being deployed earlier than the other.

Signatures created for Green Lambert (Windows) have also triggered on an OS X variant of Green Lambert, with a very low version number: 1.2.0.  This was uploaded to a multi-scanner service in September 2014.  The OS X variant of Green Lambert is in many regards functionally identical to the Windows version, but it’s missing certain functionality – such as running plugins directly in memory.

Kaspersky Lab detections for Blue, Black, and Green Lamberts have been triggered by a relatively small set of victims from around the world.  While investigating one of these infections involving White Lambert (network-driven implant) and Blue Lambert (active implant), we found yet another family of tools that appear to be related.  We called this new family ‘Pink Lambert’.

The Pink Lambert toolset includes a beaconing implant, a USB-harvesting module and a multi-platform orchestrator framework that can be used to create OS-independent malware.  Versions of this particular orchestrator were found on other victims, together with White Lambert samples, indicating a close relationship between the White and Pink Lambert families.

By looking further for other undetected malware on victims of White Lambert, we found yet another, apparently related, family.  The new family, which we called ‘Gray Lambert’, is the latest iteration of passive network tools from the Lamberts’ arsenal.  The coding style of Gray Lambert is similar to the Pink Lambert USB-harvesting module.  However, the functionality mirrors that of White Lambert.  Compared to White Lambert, Gray Lambert runs in user mode, without the need for exploiting a vulnerable signed driver to load arbitrary code on 64-bit Windows systems.

Connecting all these different families by shared code, data formats, C2 server, and victims, we have arrived at the following overarching picture:

Development of The Lamberts toolkit spans several years, with most activity occurring in 2013 and 2014.

Overall, the toolkit includes highly sophisticated malware that relies on high-level techniques to sniff network traffic, run plugins in memory without touching the disk and making use of exploits against signed drivers to run unsigned code on 64-bit Windows systems.

To further exemplify the proficiency of the attackers behind The Lamberts’ toolkit, deployment of Black Lambert included a rather sophisticated TTF zero-day exploit, CVE-2014-4148.  Taking this into account, we classify The Lamberts as the same level of complexity as Duqu, Equation, Regin or ProjectSauron – that is, one of the most sophisticated cyber-espionage toolkits we have ever analysed.

In the vast majority of cases, the infection method is unknown, so there are still a lot of unknown details about these attacks and the group(s) using them.

You can read more about The Lamberts here.

The only effective way to withstand such threats is to deploy multiple layers of security, with sensors to monitor for even the slightest anomaly in organisational workflow, combined with threat intelligence and forensic analysis.

We will continue to monitor the activities of The Lamberts, as well as other targeted attack groups.  By subscribing to our APT intelligence reports, you can get access to our investigations and discoveries as they happen, including comprehensive technical data.

Malware stories More vulnerable Internet of Things things

Hackers are targeting devices that make up the Internet of Things (IoT) more and more.  One of the most dramatic examples is the Mirai botnet, which took down a portion of the Internet in October 2016 by hijacking connected home devices (such as DVRs, CCTV cameras and printers).

In our predictions for 2017 we suggested that vigilante hackers might also target IoT devices, to draw attention to the woeful lack of security in some connected devices – perhaps even going so far as to create an ‘Internet of bricks’.  In addition, there have been recent reports (here and here) of IoT malware designed to just that.

In April, we published an analysis of the Hajime botnet.  This malware, first reported in October 2016 by Rapidity Networks, infects insecure IoT devices with open Telnet ports and default passwords.  Hajime is a huge peer-to-peer botnet which, at the time of our report (25 April) comprised around 300,000 devices.  The malware is continually evolving, adding and removing functionality.  The most intriguing aspect of Hajime is its purpose. The botnet is growing, partly due to new exploitation modules, but its purpose remains unknown.  So far, it hasn’t been used for malicious activity.  It’s possible that this will never happen, because every time a new configuration file is downloaded, a piece of text is displayed while the new configuration is being processed:

On the other hand, even if it’s not used for deliberate harm, it’s possible that it might adversely affect the normal operation of an infected device.

Hajime, like other malware designed to compromised IoT devices, exploits the fact that many people don’t change the manufacturer’s default credentials when they buy a smart device. This makes it easy for attackers to access the device – they simply have to try the known default password.  In addition, there are no firmware updates for many devices.  IoT devices are also an attractive target for cybercriminals because they often have 24/7 connectivity.

These days we’re surrounded by smart devices.  This includes everyday household objects such as telephones, televisions, thermostats, refrigerators, baby monitors, fitness bracelets and even children’s toys.   However, it also includes cars, medical devices, CCTV cameras and parking meters.  Now we can add drones to the list.

At the Security Analyst Summit, security expert Jonathan Andersson showed how a skilled attacker could create a device to hijack a drone in seconds.  He used a software-defined radio (SDR), a drone’s control unit, a microcomputer and some other electronic equipment to create such a device, which he called ‘Icarus’.  He used the device to tune to the frequency a drone uses to communicate with its controller and then experimented until he learned how exactly the signals were transmitted between the devices.

Andersson explained that this threat can potentially influence the whole drone industry — from cheap toys to expensive, professional craft — because drones and controller units use data transfer protocols that are vulnerable to the same type of attack.  While stronger encryption could fix the problem, it’s not that easy because many controllers do not support software updates.   Strong encryption also requires substantial computation capacity, which leads to additional energy consumption by the controller and the drone.

Hacking drones might seem a bit far-fetched, but the use of drones is no longer just a niche activity. Last December, Amazon tested the use of drones to deliver parcels.

You can find our overview of the growing threat to IoT devices, plus advice on protecting yourself from IoT malware here.

From extortion to ExPetr

The threat from ransomware continues to grow.  Between April 2016 and March 2017, we blocked ransomware on the computers of 2,581,026 Kaspersky Lab customers.  This is an increase of 11.4 per cent on the previous 12 months.  You can read our full report on ransomware developments in 2016-17 here, but here are some of the key trends.

  • The extortion model is here to say and we’re seeing growing competition between ransomware gangs. They’re also targeting countries that had previously been unaffected – where people are less well-prepared to deal with the threat.
  • We’re seeing increasingly targeted ransomware attacks – quite simply because attacks on businesses are more profitable.
  • Ransomware is growing in sophistication and diversity, offering many ready-to-go solutions to those with fewer skills, resources or time – through a growing and increasingly efficient underground eco-system.
  • The establishment of a criminal-to-criminal infrastructure that is fuelling the development of easy-to-go, ad hoc tools to perform targeted attacks and extort money, making attacks more dispersed.
  • Global initiatives to protect people from crypto-ransomware, such as No More Ransom, will continue to gain momentum.

In May, we saw the biggest ransomware epidemic in history, called WannaCry.  The largest number of attacks occurred in Russia, but there were also victims in Ukraine, India, Taiwan and many other countries – in total, 74 countries were affected.  The malware spread very quickly – in just one day we saw more than 45,000 infections (Europol later estimated that upwards of 200,000 people had fallen victim to WannaCry).

WannaCry spread by taking advantage of a Windows exploit named ‘EternalBlue’ that relies on a vulnerability that Microsoft had patched in security update MS17-010.  The Microsoft update had been released on 14 March, one month before EternalBlue exploit was made available in the ‘Shadow Brokers’ dump.  However, many organisations hadn’t patched their systems, allowing the attackers to gain remote access to corporate systems.  It then spread to other un-patched computers on the network.

Like other cryptors, WannaCry encrypts files on an infected computer and demands a ransom to decrypt them.

The attackers initially demanded $300, but this increased top $600 as the outbreak unfolded.

To ensure that the victims didn’t miss the warning, the malware changed the wallpaper and included instructions on how to locate the decryptor tool dropped by the malware.

It’s clear from our research that the quality of the WannaCry code is poor and the developers made many mistakes, enabling many of those infected to recover encrypted data.  The way the attackers handled ransom payments limited their ability to capitalise on the spread of the worm.  Multiple attempts were made to track transactions to the bitcoin wallets used by the attackers.  Although estimates of how much money the attackers made vary, they run into tens of thousands, rather than hundreds

The timeline for attacks in the first week shows the impact of cyber-security efforts in combating the threat.

Not least among them was the discovery of a kill-switch.  There’s a special check at the start of the code.  It tries to connect to a hard-coded web site:  if the connection fails the attack continues, if the connection is made, the code exits.  By registering this domain and pointing it to a sinkhole server, a UK researcher was able to slow the infection of the worm.

A few days into the outbreak, Neel Mehta, a researcher at Google, posted a mysterious tweet using the #WannaCryptAttribution hashtag referring to a similarity between two code samples.  One was a WannaCry sample from February 2017 that looked like an early variant of the worm.  The other was a Lazarus sample from February 2017.  Kaspersky Lab and others confirmed the similarity.  It’s too early to say for sure if WannaCry was the work of the Lazarus group – more research is required to see if the dots join up.

You can find our original blog post here, our FAQ here and our comparison of the WannaCry and Lazarus samples here.

Towards the end of June, we saw reports of a new wave of ransomware attacks.  The malware, which we called ExPetr (but known variously as Petya, Petrwrap and NotPetya) primarily targeted businesses in Ukraine, Russia and Europe – around 2,000 in total.

ExPetr uses a modified version of the EternalBlue exploit, as well as another exploit made public by the Shadow Brokers, called ‘EternalRomance’.  The malware spread as an update to MeDoc – a Ukrainian accounting application – and through watering-hole attacks.  Once inside the target organisation, the ransomware uses custom tools to extract credentials from the ‘lsass.exe’ process and passes them to PsExec or WMIC tools for further distribution within the network.

The malware waits for 10 minutes to an hour before re-booting the computer and then encrypts the MFT in NTFS partitions, overwriting the MBR with a customised loader containing a ransom demand.

ExPetr encrypts files as well as encrypting the MFT.  The attackers demanded $300 in Bitcoins for the key to decrypt ransomed data, payable to a unified Bitcoin account.  In principle – and unlike WannaCry – this technique could have worked because the attackers asked the victims to send their wallet numbers by e-mail to ‘wowsmith123456@posteo.net’, thus confirming the transactions.  However, this e-mail account was quickly shut down, limiting the scope of the attackers to make money.

Following further analysis of the encryption routine, we concluded, as did some other researchers, that it isn’t possible for the attackers to decrypt the victims’ disks, even if payment is made.  This suggests that ExPetr was a wiper masquerading as ransomware.  There is even a suggestion that there might be a connection between ExPetr and the BlackEnergy KillDisk ransomware from 2015 and 2016.

ExPetr wasn’t the only ransomware that was distributed via MeDoc updates on 27 June 27.  Another ransomware program, which we called FakeCry, was distributed to MeDoc customers at the same time.  Our data indicate that 90 organisations received this malware, nearly all of them in Ukraine.

While the interface and messages closely resemble WannaCry, it is an entirely different malware family.  We believe that FakeCry was designed with false flags in mind.  One of the most interesting questions is whether FakeCry and ExPetr are related – as is suggested by the fact that both were distributed at the same time through MeDoc updates.

Here are our recommendations on how to protect against ransomware attacks.

  • Run a robust anti-malware suite with embedded anti-ransomware protection (such as Kaspersky Lab’s System Watcher).
  • Apply security updates for your operating system and applications as soon as they become available.
  • Do not open attachments, or click on links, from untrusted sources.
  • Backup sensitive data to external storage and keep it offline.
  • Never pay the ransom. Not only does this fuel the next wave of ransomware attacks, but also there is no guarantee that the criminals will restore your data.

The return of Mamba ransomware

Wed, 08/09/2017 - 10:00

At the end of 2016, there was a major attack against San Francisco’s Municipal Transportation Agency. The attack was done using Mamba ransomware. This ransomware uses a legitimate utility called DiskCryptor for full disk encryption. This month, we noted that the group behind this ransomware has resumed their attacks against corporations.

Attack Geography

We are currently observing attacks against corporations that are located in:

  • Brazil
  • Saudi Arabia
Attack Vector

As usual, this group gains access to an organization’s network and uses the psexec utility to execute the ransomware. Also, it is important to mention that for each machine in the victim’s network, the threat executor generates a password for the DiskCryptor utility. This password is passed via command line arguments to the ransomware dropper.

Example of malware execution

Technical Analysis

In a nutshell, the malicious activity can be separated into two stages:

Stage 1 (Preparation):

  • Create folder “C:\xampp\http
  • Drop DiskCryptor components into the folder
  • Install DiskCryptor driver
  • Register system service called DefragmentService
  • Reboot victim machine

Stage 2 (Encryption):

  • Setup bootloader to MBR and encrypt disk partitions using DiskCryptor software
  • Clean up
  • Reboot victim machine
Stage 1 (Preparation)

As the trojan uses the DiskCryptor utility, the first stage deals with installing this tool on a victim machine. The malicious dropper stores DiskCryptor’s modules in their own resources.

DiskCryptor modules

Depending on OS information, the malware is able to choose between 32- or 64-bit DiskCryptor modules. The necessary modules will be dropped into the “C:\xampp\http” folder.

The malware drops the necessary modules

After that, it launches the dropped DiskCryptor installer.

The call of the DiskCryptor installer

When DiskCryptor is installed, the malware creates a service that has SERVICE_ALL_ACCESS and SERVICE_AUTO_START parameters.

The creation of the malicious service’s function

The last step of Stage 1 is to reboot the system.

Force reboot function

Stage 2 (Encryption)

Using the DiskCryptor software, the malware sets up a new bootloader to MBR.

The call for setting up a bootloader to MBR

The bootloader contains the ransom message for the victim.

Ransomware note

After the bootloader is set, disk partitions would be encrypted using a password, previously specified as a command line argument for the dropper.

The call tree of encryption processes

When the encryption ends, the system will be rebooted, and a victim will see a ransom note on the screen.

Ransom notes

Kaspersky Lab products detect this threat with the help of the System Watcher component with the following verdict: PDM:Trojan.Win32.Generic.

Decryption

Unfortunately, there is no way to decrypt data that has been encrypted using the DiskCryptor utility because this legitimate utility uses strong encryption algorithms.

IOCs:

79ED93DF3BEC7CD95CE60E6EE35F46A1

APT Trends report Q2 2017

Tue, 08/08/2017 - 10:00

Introduction

Since 2014, Kaspersky Lab’s Global Research and Analysis Team (GReAT) has been providing threat intelligence reports to a wide-range of customers worldwide, leading to the delivery of a full and dedicated private reporting service. Prior to the new service offering, GReAT published research online for the general public in an effort to help combat the ever-increasing threat from nation-state and other advanced actors.  Since we began offering a threat intelligence service, all deep technical details on advanced campaigns are first pushed to our subscriber base. At the same time, to remain true to our efforts to help make the internet safer, important incidents, such as WannaCry or Petya are covered in both private and public reports.

Kaspersky’s Private Threat Intelligence Portal (TIP)

In Q1 of 2017 we published our first APT Trends report, highlighting our top research findings over the last few months. We will continue to publish quarterly reports as a representative snapshot of what has been offered in greater detail in our private reports in order to highlight significant events and findings we feel most users should be aware of.  If you would like to learn more about our intelligence reports or request more information for a specific report, readers are encouraged to contact: intelreports@kaspersky.com.

Russian-Speaking Actors

The second quarter of 2017 has seen multiple incidents involving Russian-speaking threat actors. Topping the list of ‘attention grabbers’ were the Sofacy and Turla threat actors.

March and April started off with a bang, with the discovery of three zero-day exploits being used in-the-wild by Sofacy and Turla: two of these targeted Microsoft Office’s Encapsulated PostScript (EPS) and the third being a Microsoft Windows Local Privilege Escalation (LPE).  Sofacy was discovered utilizing both CVE-2017-0262 (an EPS vulnerability) and CVE-2017-0263 (LPE) over the Easter holiday, targeting a swath of users throughout Europe.  Prior to this attack, Turla was also discovered using CVE-2017-0261 (a different EPS vulnerability).  Neither actor appeared to deviate from their usual payload repertoire, with Sofacy dropping their typical GAMEFISH payload and Turla utilizing what we refer to as ICEDCOFFEE (a.k.a. Shirime).  Targeting for these attacks was also directly within the normal wheelhouse for both actors, focusing mainly on foreign ministries, governments, and other government-affiliated organizations.

GReAT produced additional reports on Sofacy and Turla beyond those mentioned above.  In April, we notified customers of two new experimental macro techniques utilized by Sofacy.  These techniques, while not particularly sophisticated, caught our attention as they had not been seen before in-the-wild.  The first technique involved using the built-in ‘certutil’ utility in Microsoft Windows to extract a hardcoded payload within a macro. The second technique involved embedding Base64-encoded payloads within the EXIF metadata of the malicious documents.  While the targeting for this new set of activity was again fairly standard, we discovered some noteworthy targeting against a French political party member prior to the 2017 elections.  Moving into May and June, we wrote two additional reports of interest involving these two actors: the first was an update on the long running “Mosquito Turla” campaign showing the usage of fake Adobe Flash installers and continued targeting of foreign Ministries. The other documented yet another update on Sofacy’s unique Delphi payload we call ‘Zebrocy’.

June saw the massive outbreak of a piece of malware dubbed “ExPetr”.  While initial assessments presumed that this was yet another ransomware attack à la WannaCry, a deeper assessment by GReAT places the initial intent as constituting an operation destructive in nature.  We were also able to confidently identify the initial distribution of the malware, as well as indicate a low confidence assessment that the attacks may share traits with the BlackEnergy actors. 

Below is a summary of report titles produced for the Eastern European region only.  As stated above, if you would like to learn more about our threat intelligence products or request more information on a specific report, please direct inquiries to intelreports@kaspersky.com.

  1. Sofacy Dabbling in New Macro Techniques
  2. Sofacy Using Two Zero Days in Recent Targeted Attacks – early warning
  3. Turla EPS Zero Day – early warning
  4. Mosquito Turla Targets Foreign Affairs Globally
  5. Update on Zebrocy Activity June 2017
  6. ExPetr motivation and attribution – Early alert
  7. BlackBox ATM attacks using SDC bus injection
English-Speaking Actors

English-speaking actors are always particularly fascinating due to their history of complex tooling and campaigns. Actors like Regin and Project Sauron have proven fascinating examples of new techniques leveraged in long-lasting, hard to catch campaigns and as such make ideal subjects for further research. Not to be outdone, Equation and the Lamberts were the subjects of our most recent investigations.

Continuing our practice of conducting malware paleontology while integrating new discoveries, we published a report on EQUATIONVECTOR, an Equation backdoor first used as early as 2006. This backdoor is a fascinating passive-active shellcode staging implant. It’s one of the earliest noted instances of a NObody But US (‘NOBUS’) backdoor for staging further attacks. Despite its age, the EQUATIONVECTOR backdoor (identified as ‘PeddleCheap’ in the latest ShadowBrokers disclosures) incorporates many advanced techniques for prolonged stealthy operations in victim networks, allowing the Equation operators to deliver further payloads without arousing suspicion. The report tracks the development of these tools through subsequent iterations year-by-year.

Our tracking of the Lamberts toolkit continues with the publication of the Gray Lambert report in June, the most advanced Lambert known to date. This too is a NOBUS backdoor, a passive implant operating strictly in user-land. The intricate usefulness of Gray Lambert lies in its ability to orchestrate multiple sniffer victims on a network via broadcast, multicast, and unicast commands, allowing the operators to employ surgical precision in networks with many infected machines. The sniffers double as next-stage payload delivery mechanisms for an infected network. A notable feature of the Lambert campaigns is the level of precision with which targets are chosen; Gray Lambert’s victimology is primarily focused on strategic verticals in Asia and Middle East. During this investigation, GReAT researchers have also discovered two additional Lambert families (Red Lambert and Brown Lambert) currently under investigation for Q3.  Below is a list of report titles for reference:

  1. EQUATIONVECTOR – A Generational Breakdown of the PeddleCheap Multifunctional Backdoor
  2. The Gray Lambert – A Leap in Sophistication to User-land NOBUS Passive Implants
Korean-speaking Actors

Our researchers focusing on attacks with a Korean nexus also had a very busy quarter, producing seven reports on the Lazarus group and WannaCry attacks.  Most of the reports on Lazarus directly involved a sub-group we refer to as BlueNoroff.  They are the arm that focuses mainly on financial gain, targeting banks, ATMs, and other “money-makers”.  We revealed to customers a previously unknown piece of malware dubbed ‘Manuscrypt’ used by Lazarus to target not only diplomatic targets in South Korea, but also people using virtual currency and electronic payment sites. Most recently, ‘Manuscrypt’ has become the primary backdoor used by the BlueNoroff sub-group to target financial institutions.

WannaCry also created quite a stir in the second quarter, with our analysts producing three reports and multiple blog posts on this emerging threat.  What proved most interesting to us, was the probable linkage to Lazarus group as the source of the attacks, as well as the origins of the malware.  GReAT researchers were able to trace back some of its earliest usage and show that before the ‘EternalBlue’ exploit was added to version 2, WannaCry v1 was used in spearphishing attacks months prior.  Here is a listing of our reports from Q2 on actors with a Korean nexus:

  1. Manuscrypt – malware family distributed by Lazarus
  2. Lazarus actor targets carders
  3. Lazarus-linked ATM Malware On the Loose In South Korea
  4. Lazarus targets electronic currency operators
  5. WannaCry – major ransomware attack hitting businesses worldwide – early alert
  6. WannaCry possibly tied to the Lazarus APT Group
  7. The First WannaCry Spearphish and Module Distribution
Middle Eastern Actors

While there wasn’t much high-end activity involving Middle Eastern actors, we did produce two reports revolving around the use of a zero-day exploit (CVE-2017-0199).  The most notable involved an actor we refer to as BlackOasis and their usage of the exploit in-the-wild prior to its discovery.  We have previously reported on BlackOasis using other zero-days in the past; CVE-2016-4117 in May 2016, CVE-2016-0984 in June 2015, and CVE-2015-5119 in June 2015.  It is believed that BlackOasis is a customer of Gamma Group and utilizes the popular ‘lawful surveillance’ kit FinSpy.  Other than the usage of the exploit, this report was significant because it also showed one of the earliest known uses of a new version of FinSpy, which is still being analyzed by our researchers.

After the discovery of CVE-2017-0199, a plethora of threat actors also began to leverage this exploit in their attacks.  We reported to customers on the usage of this exploit by a well-known Middle Eastern actor dubbed ‘OilRig’.  OilRig has actively targeted many organizations in Israel with the exploit via spearphishes appearing to originate from well-known doctors within Ben Gurion University.  While their execution was less than stellar, it highlighted the widespread usage of this exploit shortly after its discovery.

  1. OilRig exploiting CVE-2017-0199 in new campaign
  2. BlackOasis using Ole2Link zero day exploit in the wild
Chinese-Speaking Actors

On the Chinese speaking front, we felt it necessary to produce two reports to our customers.  While Chinese speaking actors are active on a daily basis, not much has changed and we prefer to avoid producing reports on ‘yet another instance of APTxx’ for the sake of padding our numbers.  Instead we try to focus on new and exciting campaigns that warrant special attention.

One of those reports detailed a new finding regarding a fileless version of the well-known ‘HiKit’ malware dubbed ‘Hias’.  We have reported on Hias in the past, and one of our researchers was finally able to discover the persistence mechanism used, which also allowed us to tie the activity to an actor we call ‘CloudComputating’.

Another report detailed a new campaign we referred to as ‘IndigoZebra’.  This campaign was targeting former Soviet Republics with a wide swath of malware including Meterpreter, Poison Ivy, xDown, and a previously unknown malware called ‘xCaon’.  This campaign shares ties with other well-known Chinese-speaking actors, but no definitive attribution has been made at this time.

  1. Updated technical analysis of Hias RAT
  2. IndigoZebra – Intelligence preparation to high-level summits in Middle Asia
Best of the rest

Sometimes we find new and exciting campaigns or entirely new threat actors to report to our subscribers without being able to make an immediate or definitive determination on regional provenance.  Several reports fell into this category in the last quarter.  ChasingAdder is a report describing a new persistence technique that hijacked a legitimate WMI DLL for the purposes of loading a malicious payload. This activity targeted high-profile diplomatic, military, and research organizations beginning in the fall of 2016, but to date we have not been able to pinpoint the specific actor responsible.

Demsty is a new piece of MacOS malware that is targeting University researchers in Hong Kong, among others.  At the time of writing, we have a low confidence assessment that the campaign was conducted by Chinese-speaking actors, and thus categorize this as ‘Unknown’ until greater evidence comes to light.

During Q2, the mischievous ShadowBrokers also continued their regular activities dumping multiple tools and documentation allegedly stolen from Equation Group. In April, the ShadowBrokers released another dump of information detailing the alleged targeting of SWIFT service bureaus and other banks by Equation Group.  Since some of our customers are financial entities, we found it necessary to evaluate the data and provide an expert’s opinion on the validity of the dump.

Reports in the ‘unknown’ category:

  1. ShadowBrokers’ Lost in translation leak – SWIFT attacks analysis
  2. ChasingAdder – WMI DLL Hijacking Trojan Targeting High Profile Victims
  3. University Researchers Located in Hong Kong Targeted with Demsty
Predictions

Based on the trends we’ve seen over the last three months, as well as foreseeable geopolitical events, we have listed a few predictions for the upcoming quarter (Q3). As always, this isn’t an exact science and some cases won’t come to fruition. Analyzing current and future events and combining those with the motivations of known active actors can help organizations prepare for likely forthcoming activity:

  1. Misinformation campaigns will remain a threat to countries with upcoming elections, specifically Germany and Norway, as they have been previous targets for Eastern European based actors.
  2. ‘Lawful Surveillance’ tools will continue to be utilized by governments that don’t have well-established Cyber Operations capabilities, mainly based out of the Middle East. Companies such as Gamma Group, Hacking Team, and NSO will continue to offer new zero-day exploits to those customers. As prices increase and exchanges thrive, new organizations and marketplaces will continue popping up.
  3. Destructive malware disguised as ransomware will continue to be a problem. In the last quarter we’ve seen two instances of this, and with the continued release of tools / exploits from dumps like Vault7 and ShadowBrokers, this is going to be a new alarming trend to deal with.
  4. In China, the past months have been marked by the dwindling economic growth, rising tensions with North Korea and the US, and increased exchanges between South Korean / Japanese / American organizations. In addition to these, the 19th Party Congress is set to be held in the fall of 2017 and according to multiple public predictions, it is likely that some major changes will happen in the leadership. It’s possible that these events will have wide regional influences that could affect the way that threat actors operate in Asia, both in terms of targeting and TTPs.
  5. Targeting energy-related companies and organizations will be on the rise. Countries such as Norway may be a top target moving forward given their control on oil and gas in the region in the buildup to an election. Saudi Arabia will also top the charts for potential targeting as they have in years past.
  6. Lower-tier threat actors continue to increase cyber-espionage efforts and capabilities both in complexity and size. Expect more activity with varied technical capabilities coming from lesser known or previously unseen actors.
How to keep yourself protected

One of the biggest problems when it comes to leveraging threat intelligence is judging the quality of the data and how it can be used for defense. For instance, we may observe an increase in the number of fileless attacks or attacks in which all IOCs are unique or specific per victim. In such situations, having not only host-based IOCs, but also network IOCs and Yara rules that can help identify malware in all cases is very important.

Another problem comes from the fact that many threat intelligence providers have a limited world view and their data covers only a small set of threats. It’s easy for an enterprise to fall into the trap of thinking that ‘actor X’ is not something they need to worry because their focus has been only certain countries or certain industry sectors; only to discover later that their ignorance left them blind to those attacks.

As shown by many incidents, but especially by WannaCry and ExPetr’s EternalBlue-based spreading subroutines, vulnerabilities remain a key approach to infecting systems. Therefore timely patching is of utmost importance – which, being one of the most tedious IT maintenance tasks, works much better with good automation. Kaspersky Endpoint Security for Business Advanced and Kaspersky Total Security include Vulnerability & Patch management components, offering convenient tools for making patching much easier, and much less time-consuming for IT staff.

Given the above, it is highly recommended that prevention (such as endpoint protection) along with advanced detection capabilities, such as a solution that can detect all types of anomalies and scrutinize suspicious files at a deeper level, be present on users’ systems. The Kaspersky Anti Targeted Attack solution (KATA) matches events coming from different infrastructure levels, discerns anomalies and aggregates them into incidents, while also studying related artifacts in a safe environment of a sandbox. As with most Kaspersky products, KATA is powered by HuMachine Intelligence, which is backed by on premise and in lab-running machine learning processes coupled with real-time analyst expertise and our understanding of threat intelligence big data.

The best way to prevent attackers from finding and leveraging security holes, is to eliminate the holes altogether, including those involving improper system configurations or errors in proprietary applications. For this, Kaspersky Penetration Testing and Application Security Assessment services can become a convenient and highly effective solution, providing not only data on found vulnerabilities, but also advising on how to fix it, further strengthening corporate security.

Steganography in contemporary cyberattacks

Thu, 08/03/2017 - 05:00

Steganography is the practice of sending data in a concealed format so the very fact of sending the data is disguised. The word steganography is a combination of the Greek words στεγανός (steganos), meaning “covered, concealed, or protected”, and γράφειν (graphein) meaning “writing”.

Unlike cryptography, which conceals the contents of a secret message, steganography conceals the very fact that a message is communicated. The concept of steganography was first introduced in 1499, but the idea itself has existed since ancient times. There are stories of a method being used in the Roman Empire whereby a slave chosen to convey a secret message had his scalp shaved clean and a message was tattooed onto the skin. When the messenger’s hair grew back, he was dispatched on his mission. The receiver shaved the messenger’s scalp again and read the message.

In this article, the following definitions are used:

  • Payload: the information to be concealed and sent secretly, or the data covertly communicated;
  • Carrier (stego-container): any object where the payload is secretly embedded;
  • Stego-system: the methods and means used to create a concealed channel for communicating information;
  • Channel: the data communication channel via which the carrier is transferred;
  • Key: the key used to extract the payload from the carrier (not always applied).

Steganography was actively developed throughout the 20th century, as was steganalysis, or the practice of determining the fact that concealed information is being communicated within a carrier. (Basically, steganalysis is the practice of attacking stego-systems.) Today, however, a dangerous new trend is emerging: steganography is increasingly being used by actors creating malware and cyber-espionage tools. Most modern anti-malware solutions provide little, if any, protection from steganography, while any carrier in which a payload can be secretly carried poses a potential threat. It may contain data being exfiltrated by spyware, communication between a malicious program and its C&C, or new malware.

A variety of steganographic methods and algorithms have been scientifically developed and tested. A description of some of them is provided below.

  • In LSB steganography, the payload is encoded into and communicated in one or several least significant bits of the carrier. The smaller the number of bits used to carry the payload, the lower the impact on the original carrier signal.
  • Discrete cosine transform or DCT-based steganography is a sub-type of LSB steganography that is often applied on JPEG-format carriers (i.e., when JPEG images are used to carry the payload). In this method, the communicated data is secretly encoded into the DCT coefficients. With all other factors being equal, this method provides a somewhat lower data carrying capacity; one of the reasons for this is that the coefficient values of 0 and 1 cannot be altered, so no data can be encoded whenever the coefficients take on these values.
  • Palette-based image steganography is basically another sub-type of LSB steganography, in which the communicated data is encoded into least significant bits of the image palette rather than into those of the carrier. The obvious downside to this method is its low data carrying capacity.
  • Use of service fields in data formats. This is a relatively simple method, in which the payload is embedded into the service fields of the carrier’s headers. The downsides are, again, a low data carrying capacity and low payload protection: the embedded payload may be detected using regular image viewing software that can sometimes display the contents of the service fields.
  • Payload embedding is a method whereby the payload is encoded into the carrier and, upon delivery, is decoded using an algorithm known to both parties. Several payloads can be independently encoded into the same carrier provided that their embedding methods are orthogonal.
  • Wideband methods fall into the following types:
    • Pseudorandom sequence method, in which a secret carrier signal is modulated by a pseudorandom signal.
    • Frequency hopping method, in which the frequency of the carrier signal changes according to a specific pseudorandom law.
  • Overlay method – strictly speaking, this is not proper steganography, and is based on the fact that some data formats contain data size in a header, or the fact that the handler of such formats reads the file till it reaches the end-of-data marker. An example is the well-known RAR/JPEG method based on concatenating an image file, so that it is composed of a JPEG format section, followed by a RAR archive section. A JPEG viewer software program will read it till the boundary specified in the file’s header, while a RAR archiver tool will disregard everything prior to the RAR! signature that denotes the beginning of an archive. Therefore, if such a file is opened in an image file viewer, it will display the image, and if it is opened in a RAR archiver, it will display the contents of the RAR archive. The downside to this method is that the overlay added to the carrier segment can be easily identified by an analyst visually reviewing the file.

In this article, we will only review methods of concealing information in image-type carriers and in network communication. The application of steganography is, however, much wider than these two areas.

Recently, we have seen steganography used in the following malware programs and cyberespionage tools:

  • Microcin (AKA six little monkeys);
  • NetTraveler;
  • Zberp;
  • Enfal (its new loader called Zero.T);
  • Shamoon;
  • KinS;
  • ZeusVM;
  • Triton (Fibbit).

So why are malware authors increasingly using steganography in their creations? We see three main reasons for this:

  • It helps them conceal not just the data itself but the fact that data is being uploaded and downloaded;
  • It helps bypass DPI systems, which is relevant for corporate systems;
  • Use of steganography may help bypass security checks by anti-APT products, as the latter cannot process all image files (corporate networks contain too many of them, and the analysis algorithms are rather expensive).

For the end user, detecting a payload within a carrier may be a non-trivial task. As an example, let’s review the two images below. One is an empty carrier, and the other is a carrier with a payload. We will use the standard test image Lenna.

Lenna.bmp Lenna_stego.bmp

Both images are 786 486 bytes; however, the right-hand image contains the first 10 chapters of Nabokov’s novel Lolita.

Take a good look at these two images. Can you see any difference? They are identical in both size and appearance. However, one of them is a carrier containing an embedded message.

The problems are obvious:

  • Steganography is now very popular with malware and spyware writers;
  • Anti-malware tools generally, and perimeter security tools specifically, can do very little with payload-filled carriers. Such carriers are very difficult to detect, as they look like regular image files (or other types of files);
  • All steganography detection programs today are essentially proof-of-concept, and their logic cannot be implemented in commercial security tools because they are slow, have fairly low detection rates, and sometimes even contain errors in the math (we have seen some instances where this was the case).

A list was provided above (though it does not claim to be complete) of malicious programs that use steganography to conceal their communication. Let’s review one specific case from that list, the malicious loader Zero.T.

We detected this loader in late 2016, though our colleagues from Proofpoint were first to publish a description.

We named it Zero.T because of this string in its executable code (in the path leading to the project’s PBD file):

We will not dwell here on how the malicious loader penetrates the victim system and remains there, but will note that it loads a payload in the form of Bitmap files:

Then it processes them in a particular way to obtain malicious modules:

On the face of it, these three BMP files appear to be images:

However, they are more than just regular images; they are payload-filled carriers. In each of them, several (the algorithm allows for variability) least significant bits are replaced by the payload.

So, is there a way to determine whether an image is carrying a malicious payload or not? Yes, there are several ways of doing so, the simplest being a visual attack. It is based on forming new images from the source image, containing the least significant bits of different color planes.

Let’s see how this works using the Steve Jobs photo as a sample image.

We apply a visual attack to this image and construct new images from the separate significant bits in the appropriate order:

In the second and the third images, high entropy (high data density) areas are apparent – these contain the embedded payload.

Sounds simple, right? Yes and no. It’s simple in that an analyst – and even an average user – can easily see the embedded data; it’s difficult in that this sort of analysis is not easy to automate. Fortunately, scientists have long since developed a number of methods for detecting carriers with payloads, based on an image’s statistical characteristics. However, all of them are based on the assumption that the encoded payload has high entropy. This is true in most cases: since the container’s capacity is limited, the payload is compressed and/or encrypted before encoding, thus increasing its entropy.

However, our real-life example, the malicious loader Zero.T, does not compress its malicious modules before encoding. Instead, it increases the number of least significant bits it uses, which can be 1, 2 or 4. Yes, using a larger number of least significant bits introduces visual artefacts into the carrier image, which a regular user can detect visually. But we are talking about automatic analysis. So, the question we have to answer is: are statistical methods suitable for detecting embedded payloads with low levels of entropy?

Statistical methods of analysis: histogram method

This method was suggested in 2000 by Andreas Westfeld and Andreas Pfitzmann, and is also known as the chi-squared method. Below we give a brief overview.

The entire image raster is analyzed. For each color, the number of dots possessing that color is counted within the raster. (For simplicity, we are dealing with an image with one color plane.) This method assumes that the number of pixels possessing two adjacent colors (i.e. colors different only by one least significant bit) differs substantially for a regular image that does not contain an embedded payload (see Figure A below). For a carrier image with a payload, the number of pixels possessing these colors is similar (see Figure B).

Figure A. An empty carrier Figure B. A filled carrier.

The above is an easy way to visually represent this algorithm.

Strictly speaking, the algorithm consists of the following steps that must be executed sequentially:

  • The expected occurrence frequency for the pixels of color i in a payload-embedded image is calculated as follows:
  • The measured frequency of the occurrence of a pixel of specific color is determined as:
  • The chi-squared criterion for k-1 degrees of freedom is calculated as:
  • P is the probability that the distributions ni and ni* are equal under these conditions. It is calculated by integrating the density function:

Naturally, we have tested whether this method is suitable for detecting filled stego-containers. Here are the results.

Original image Visual attack image Chi-squared attack, 10 zones

The threshold values of the chi-squared distribution for p=0.95 and p=0.99 are 101.9705929 and 92.88655838 respectively. Thus, for the zones where the calculated chi-squared values are lower than the threshold, we can accept the original hypothesis “adjacent colors have similar frequency distributions, therefore we are dealing with a carrier image with a payload”.

Indeed, if we look at the visual attack images, we can clearly see that these zones contain an embedded payload. Thus, this method works for high-entropy payloads.

Statistical methods of analysis: RS method

Another statistical method of detecting payload carriers was suggested by Jessica Fridrich, Miroslav Goljan and Andreas Pfitzmann in 2001. It is called the RS method, where RS stands for ‘regular/singular’.

The analyzed image is divided into a set of pixel groups. A special flipping procedure is then applied for each group. Based on the values of the discriminant function before and after the flipping procedure is applied, all groups are divided into regular, singular and unusable groups.

This algorithm is based on the assumption that the number of regular and singular pixel groups must be approximately equal in the original image and in the image after flipping is applied. If the numbers of these groups change appreciably after flipping is applied, this indicates that the analyzed image is a carrier with a payload.

The algorithm consists of the following steps:

  • The original image is divided into groups of n pixels (x1, …, xn).
  • The so-called discriminant function is defined which assigns to each group of pixels G = (x1, …, xn) a real number f(x1, …, xn) ∈
  • The discriminant function for the groups of pixels (x1, …, xn) can be defined as follows:
  • Then we define the flipping function which has the following properties:

Depending on the discriminant function’s values prior to and after flipping is applied, all groups of pixels are divided into regular, singular and unusable groups:

We have put this method to the test as well, and obtained the following results. We used the same empty and payload-embedded carriers as in the previous test.

Original image Visual attack image Chi-squared attack, 10 zones

Note that this attack method does not pass the binary verdict in terms of “whether this specific carrier contains an embedded payload or not”; rather, it determines the approximate length of the embedded payload (as a percentage).

As can be seen from the results above, this method returned a verdict for the empty message that it was filled less than 1% with payload, and for the payload-embedded carrier it returned a verdict that it was about 44% filled. Obviously, these results are slightly off. Let’s look at the filled container: from the visual attack it follows that more than 50% of the container is filled, while the RS attack tells us that 44% of the container is filled. Therefore, we can apply this method if we establish a certain “trigger threshold”: our experiments showed that 10% is a sufficient threshold of reliability. If the RS attack claims that more than 10% of the container is full, you can trust this verdict and mark the container as full.

Now it’s time to test these two methods in real-world conditions, on the Zero.T carriers in which the payload has regular entropy.

We ran the appropriate tests and here are the results:

Original image Chi-squared attack RS attack

As we see, a chi-squared attack is not applicable on low entropy images – it yields unsatisfactory or inaccurate results. However, the RS attack worked well: in both cases, it detected a hidden payload in the image. However, what do we do if automatic analysis methods show there is no payload, but we still suspect there might be one?

In that case, we can apply specific procedures that have been developed for specific malware families to extract the payload. For the aforementioned Zero.T loader, we have written our own embedded payload extraction tool. Its operation can be schematically presented as follows.

+ =

Obviously, if we get a valid result (in this specific case, an executable file), then the source image has an embedded payload in it.

Is DNS tunneling also steganography?

Can we consider use of a DNS tunnel a subtype of steganography? Yes, definitely. For starters, let’s recap on how a DNS tunnel works.

From a user computer in a closed network, a request is sent to resolve a domain, for example the domain wL8nd3DdINcGYAAj7Hh0H56a8nd3DdINcGYAlFDHBurWzMt[.]imbadguy[.]com to an IP address. (In this URL, the second-level domain name is not meaningful.) The local DNS server forwards this request to an external DNS server. The latter, in turn, does not know the third-level domain name, so it passes this request forward. Thus, this DNS request follows a chain of redirections from one DNS server to another, and reaches the DNS server of the domain imbadguy[.]com.

Instead of resolving a DNS request at the DNS server, threat actors can extract the information they require from the received domain name by decoding its first part. For example, information about the user’s system can be transmitted in this way. In response, a threat actor’s DNS server also sends some information in a decoded format, putting it into the third- or higher-level domain name.

This means the attacker has 255 characters in reserve for each DNS resolution, up to 63 characters for subdomains. 63 characters’ worth of data is sent in each DNS request, and 63 characters are sent back in response, and so on. This makes it a decent data communications channel! Most importantly, it is concealed communication, as an unaided eye cannot see that any extra data is being communicated.

To specialists who are familiar with network protocols and, in particular, with DNS tunneling, a traffic dump containing this sort of communication will look quite suspicious – it will contain too many long domains that get successfully resolved. In this specific case, we are looking at the real-life example of traffic generated by the Trojan Backdoor.Win32.Denis, which uses a DNS tunnel as a concealed channel to communicate with its C&C.

A DNS tunnel can be detected with the help of any popular intrusion detection (IDS) tool such as Snort, Suiricata or BRO IDS. This can be done using various methods. For example, one obvious idea is to use the fact that domain names sent for DNS resolution are much longer than usual during tunneling. There are quite a few variations on this theme on the Internet:

alert udp any any -> any 53 (msg:”Large DNS Query, possible cover channel”; content:”|01 00 00 01 00 00 00 00 00 00|”; depth:10; offset:2; dsize:>40; sid:1235467;)

There is also this rather primitive approach:

Alert udp $HOME_NET and -> any 53 (msg: “Large DNS Query”; dsize: >100; sid:1234567;)

There is plenty of room for experimenting here, trying to find a balance between the number of false positives and detecting instances of actual DNS tunneling.

Apart from suspiciously long domain names, what other factors may be useful? Well, anomalous syntax of domain names is another factor. All of us have some idea of what typical domain names look like – they usually contain letters and numbers. But if a domain name contains Base64 characters, it will look pretty suspicious, won’t it? If this sort of domain name is also quite long, then it is clearly worth a closer look.

Many more such anomalies can be described. Regular expressions are of great help in detecting them.

We would like to note that even such a basic approach to detecting DNS tunnels works very well. We applied several of these rules for intrusion detection to the stream of malware samples sent to Kaspersky Lab for analysis, and detected several new, previously unknown backdoors that used DNS tunnels as a covert channel for C&C communication.

Conclusions

We are seeing a strong upward trend in malware developers using steganography for different purposes, including for concealing C&C communication and for downloading malicious modules. This is an effective approach considering payload detection tools are probabilistic and expensive, meaning most security solutions cannot afford to process all the objects that may contain steganography payloads.

However, effective solutions do exist – they are based on combinations of different methods of analysis, prompt pre-detections, analysis of meta-data of the potential payload carrier, etc. Today, such solutions are implemented in Kaspersky Lab’s Anti-Targeted Attack solution (KATA). With KATA deployed, an information security officer can promptly find out about a possible targeted attack on the protected perimeter and/or the fact that data is being exfiltrated.

DDoS attacks in Q2 2017

Tue, 08/01/2017 - 05:00

News Overview

The second quarter of 2017 saw DDoS attacks being more and more frequently used as a tool for political struggle. The Qatar crisis was accompanied by an attack on the website of Al Jazeera, the largest news network in the area, Le Monde and Le Figaro websites were targeted in the heat of the presidential election in France, and in Great Britain they recalled a year-old incident with the Brexit voter registration website where some citizens were excluded from the referendum because of the continuous attacks on the website.

Quite a significant event took place in the USA: the Federal Communications Commission (FCC) revealed plans for abolishing the principle of net neutrality, legislatively mandated two years before. The public comment system of the Commission website was rendered inoperative for about a day and eventually was completely disabled as a result of a massive attack. The reason for the crash remained unclear: it was either an invasion of the opponents of net neutrality, who were flooding the system with identical comments, or, on the contrary, an attack launched by the supporters of net neutrality, who tried to prevent their adversaries from flooding the FCC website with fake comments.

And yet, money remains the driving force of DDoS attacks. The growing interest in cryptocurrencies led to an increase in their exchange-value in the second quarter of 2017, which in turn drew the attention of cybercriminals. The largest bitcoin exchange, Bitfinex underwent an attack at the same time as the trading of a new IOT-currency IOTA was launched. Somewhat earlier the BTC-E exchange stated that its services were slowed down because of a powerful DDoS attack. Apparently, this way cybercriminals attempt to manipulate the currency rates, which can be quite easily achieved considering the high volatility of cryptocurrencies.

Owners of DDoS botnets do not limit themselves to renting out their computing powers. At the end of June, there was registered a large-scale attempt of extortion under threat of a DDoS attack. The group that calls itself Armada Collective demanded about $315,000 from seven South Korean banks in exchange for not disrupting their online services. According to a Radware report, this was not the first case of extortion through a DDoS attack initiated by this group.

With growing financial losses from DDoS attacks law enforcement agencies begin to take the attack initiators more seriously. In April 2017 in Great Britain, a young man was sentenced to two years in prison for a series of attacks, which he had carried out five years before while still being a student. The man had created the Titanium Stresser botnet and traded its services on a darknet, thus yielding a profit of approximately £386,000.

There were not many technical innovations in DDoS attacks in the second quarter; however, news concerning a new DDoS-attack vector deserves attention. Researchers from Corero Network Security reported that they had registered more than 400 attacks with the help of misconfigured LDAP servers. The largest attack volume was at 33 Gb/s. As amplified reflection was used in that case, the organization of such attacks requires relatively few resources.

The most infamous attack of the second quarter became a DDoS attack on Skype servers. Many users of the messenger all over the world experienced connectivity problems. The responsibility for the campaign was claimed by CyberTeam, but its motives remain unknown.

Quarter Trends Ransom DDoS

The trend of extorting money under threat of DDoS attacks is becoming more prominent during this quarter. This approach was dubbed “ransom DDoS”, or “RDoS”. Cybercriminals send a message to a victim company demanding a ransom of 5 to 200 bitcoins. In case of nonpayment, they promise to organize a DDoS attack on an essential web resource of the victim. Such messages are often accompanied by short-term attacks which serve as demonstration of the attacker’s power. The victim is chosen carefully. Usually, the victim is a company which would suffer substantial losses if their resources are unavailable.

There is another method as opposed to the above-mentioned one: hoping to gain revenue quickly and without much effort cybercriminals contact a great number of companies by sending out ransom messages with threats of launching a DDoS attack, not taking into account the specifics of these companies’ operation. In most cases, they do not launch a demonstrative attack. Paying the ransom would create a certain reputation for a company and provoke further attacks of other cybercriminal groups.

It should be noted that these groups now are more and more represented not by well-coordinated hacker professional teams but by beginners who do not even possess the skills to launch a DDoS attack and only have the means for a “demonstrative attack”. Those who fall victim to this scheme are companies that for one reason or another have no resources to organize security for their services yet capable of parting with available funds in order to pay the ransom.

SambaCry

There is yet another important event of the quarter, which is the discovery of a vulnerability in the Samba network software. The vulnerability allows cybercriminals to execute code remotely on devices running Linux and Unix. Samba is a software suite that allows addressing network disks and printers and runs on a majority of Unix-like operating systems, such as Linux, POSIX-compatible Solaris and Mac OS X Server and various BSD OSes.

According to the Samba company, “all versions of Samba from 3.5.0 onwards have a remote code-execution vulnerability, allowing a malicious client to upload a shared library to a writable share, and then cause the server to load and execute it”.

The total number of devices with the vulnerable software reaches over 500,000, roughly estimated. This means that cybercriminals can use the devices to create botnets with the goal of carrying out large-scale DDoS attacks.

Statistics for botnet-assisted DDoS attacks Methodology

Kaspersky Lab has extensive experience of combating cyber threats, including DDoS attacks of various complexity types and ranges. The experts of the company have been tracking the actions of botnets by using the DDoS Intelligence system.

Being part of the Kaspersky DDoS Prevention solution, the DDoS Intelligence system is intended to intercept and analyze commands sent to bots from command-and-control servers and requires neither infecting any user devices nor the actual execution of cybercriminals’ commands.

This report contains DDoS Intelligence statistics for the second quarter of 2017.

In the context of this report, it is assumed that an incident is a separate (single) DDoS-attack if the interval between botnet activity periods does not exceed 24 hours. For example, if the same web resource was attacked by the same botnet with an interval of 24 hours or more, then this incident is considered as two attacks. Also, bot requests originating from different botnets but directed at one resource count as separate attacks.

The geographical locations of DDoS-attack victims and C&C servers that were used to send commands are determined by their respective IP addresses. The number of unique targets of DDoS attacks in this report is counted by the number of unique IP addresses in the quarterly statistics.

It is important to note that DDoS Intelligence statistics are limited only to those botnets that have been detected and analyzed by Kaspersky Lab. It should also be noted that botnets are just one of the tools for performing DDoS attacks; thus, the data presented in this report do not cover every single DDoS attack occurred during the indicated period.

Q2 summary
  • The resources in 86 countries were attacked in Q2 2017, 14 countries increase over the Q1 2017.
  • Just as in Q1, almost one-half of the attacks (47.42%) were aimed at the targets in China.
  • China, South Korea, and the USA remained leaders by both the number of attacks and the number of targets. According to the number of reported C&C servers, the same countries are in the TOP 3; but South Korea took the first place this time.
  • The long-term DDoS attacks made it back in Q2. The record duration was 277 hours, which was a 131% increase compared to Q1. At the same time, the share of the attacks that lasted less than 50 hours remained practically unchanged (99.7% in Q2 vs. 99.8% in Q1).
  • There was a considerable drop in the share of attacks over TCP (down to 18.2% from 26.6%) and ICPM (down to 7.3% from 8.2%). This caused a rise in the percentage of SYN floods and attacks over UDP and HTTP.
  • Linux botnets recovered from the decline of their share in Q1. Those botnets were responsible for 51.23% of attacks in Q2 compared to 43.40% in Q1.
Geography of attacks

DDoS attacks were registered in 86 countries in Q2, where the largest number of the attacks were aimed at China (58.07% of all of the attacks), which is 3 p.p. higher compared to the previous quarter. South Korea went down from 22.41% to 14.17% and retained second place nonetheless, while the USA rose from 11.37% up to 14.03%, almost catching up with South Korea.

The top 10 accounted for 94.60% of attacks and included Italy (0.94%) and Netherlands (0.84%), pushing down Vietnam and Denmark in Q2. Russia (1.60%) lost 0.37 p.p., moving down from fourth to sixth place, while Great Britain went up from 0.77% to 1.38%, a rise from seventh to fifth place.

Distribution of DDoS attacks by country, Q1 2017 vs. Q2 2017

95.3% of the attacks were aimed at targets in the countries of top 10 in Q2 2017.

Distribution of unique DDoS-attack targets by country, Q1 2017 vs. Q2 2017

China maintained its leading position in distribution by number of targets: 47.42% of them were located in the territory of the country, a fall of 0.36 p.p. compared to Q1. At the same time, the USA pushed down South Korea by going up from third to second place. Respectively, the USA rose to 18.63% (vs. 13.80% in Q1), while South Korea went from 26.57% down to 16.37%.

The share of targets located in the territory of Russia dropped from 1.55% in Q1 to 1.33% in Q2, pushing Russia down from fifth to seventh place. Vietnam and Denmark left the top 10 and were replaced by Italy (1.35%) and Australia (0.97%).

Dynamics of the number of DDoS attacks

The number of attacks per day ranged from 131 (April 17) to 904 (April 13) in Q2 2017. The peak numbers were registered on April 24 (581), May 7 (609), June 10 (614), and June 16 (621). A relative downturn was registered on April 14 (192), May 31 (240), and June 23 (281).

Dynamics of the number of DDoS attacks in Q2 2017*
*Since DDoS attacks may continuously last for several days, one attack may be counted several times in the timeline, i.e., once per day.

Monday stayed as the quietest day for DDoS attacks (11.74% of all of the attacks) in Q2 2017, while Sunday became the busiest day (15.57%) on account of the activity slacking on Saturday, a fall from 16.05% in Q1 to 14.39% in Q2. Thursday became the second busiest day, coming right behind Sunday (15.39%).

Distribution of DDoS attacks by day of the week

Types and duration of DDoS attacks

SYN floods partially recovered their positions lost during the previous quarter, rising from 48.07% to 53.26% in Q2 2017. There was an increase of percentage for both UDP attacks (from 8.71% up to 11.91%) and HTTP attacks (from 8.43% up to 9.38%). At the same time, the share of TCP DDoS attacks plummeted from 26.62% down to 18.18%, while the popularity of ICMP attacks slightly decreased from 8.17% down to 7.27% (out of all of the registered attacks).

Distribution of DDoS attacks by type

Long-term attacks made it back to the statistics in Q2 2017: 0.07% of the attacks lasted more than 100 hours, while the record attack continued for 277 hours, 157 hours longer than the record of the previous quarter. At the same time, the share of attacks that lasted 4 hours or less increased from 82.21% in Q1 to 85.93% in Q2. Thus, the percentage of attacks lasting from 5 to 49 hours decreased.

Distribution of DDoS attacks by duration (hours)

C&C servers and botnet types

The top 3 countries with the greatest number of detected C&C servers was slightly changed in Q2: China retained the third place with its 7.74%, ousting Netherlands, which moved down to fourth place despite an increase from 3.51% to 4.76%. South Korea kept its leading position and saw a fall from 66.49% down to 49.11%, while the USA still retained the second place (16.07%). The top 3 countries accounted for 72.92% of C&C servers in total.

The top 10 included Canada and Denmark (each at 0.89%), ousting Romania and Great Britain in Q2. Compared to Q1 2017, there was a significant decrease in the shares of Hong Kong (down to 1.19% from 1.89%) and Russia (down to 2.68% from 3.24%).

Distribution of botnet C&C servers by country in Q2 2017

Distribution by operating system became almost balanced in Q2: the share of Linux-based botnets comprised 51.23%; accordingly, Windows-based botnets comprised 48.77%.

Correlation between Windows- and Linux-based botnet attacks

Conclusions

There were no particular changes in the statistics of the second quarter of 2017 when compared to the previous quarter. As before about one half of DDoS attacks still originated in China, also in China was one half of the detected attack targets.

The second quarter quite clearly showed that the DDoS-attack threat is perceived rather seriously. Some companies were prepared to pay cybercriminals literally after their first demand without waiting for the attack itself. This set off a whole new wave of fraud involving money extortion under threat of a DDoS attack, also known as “ransom DDoS”. The gravity of the situation can be seen in the cybercriminals’ frequent disregard for demonstrating their capabilities; instead, the fraudsters would just send out ransom messages directed at a large pool of addresses. Certainly, the “entry threshold” for ransom DDoS is extremely low, fraudsters need neither significant resources nor technical skills or knowledge.

A new era in mobile banking Trojans

Mon, 07/31/2017 - 05:00

In mid-July 2017, we found a new modification of the well-known mobile banking malware family Svpeng – Trojan-Banker.AndroidOS.Svpeng.ae. In this modification, the cybercriminals have added new functionality: it now also works as a keylogger, stealing entered text through the use of accessibility services.

Accessibility services generally provide user interface (UI) enhancements for users with disabilities or those temporarily unable to interact fully with a device, perhaps because they are driving. Abusing this system feature allows the Trojan not only to steal entered text from other apps installed on the device, but also to grant itself more permissions and rights, and to counteract attempts to uninstall the Trojan.

Attack data suggests this Trojan is not yet widely deployed. In the space of a week, we observed only a small number of users attacked, but these targets spanned 23 countries. Most attacked users were in Russia (29%), Germany (27%), Turkey (15%), Poland (6%) and France (3%). It is worth noting that, even though most attacked users are from Russia, this Trojan won’t work on devices running the Russian language. This is a standard tactic for Russian cybercriminals looking to evade detection and arrest.

The Svpeng malware family is known for being innovative. Starting from 2013, it was among the first to begin attacking SMS banking, to use phishing pages to overlay other apps to steal credentials, and to block devices and demand money. In 2016, cybercriminals were actively distributing Svpeng through AdSense using a vulnerability in the Chrome browser. This makes Svpeng one of the most dangerous mobile malware families, and it is why we monitor the functionality of new versions.

The attack process

After starting, the Trojan-Banker.AndroidOS.Svpeng.ae checks the device language and, if it is not Russian, asks the device for permission to use accessibility services. In abusing this privilege, it can do many harmful things. It grants itself device administrator rights, draws itself over other apps, installs itself as a default SMS app, and grants itself some dynamic permissions that include the ability to send and receive SMS, make calls, and read contacts. Furthermore, using its newly-gained abilities the Trojan can block any attempt to remove device administrator rights – thereby preventing its uninstallation. It is interesting that in doing so it also blocks any attempt to add or remove device administrator rights for any other app too.

Svpeng was able to become a device administrator without any interaction with the user just by using accessibility services.

Using accessibility services allows the Trojan to get access to the UI of other apps and to steal data from them, such as the names of the interface elements and their content, if it is available. This includes entered text. Furthermore, it takes screenshots every time the user presses a button on the keyboard, and uploads them to the malicious server. It supports not only the standard Android keyboard but also a few third-party keyboards.

Some apps, mainly banking ones, do not allow screenshots to be taken when they are on top. In such cases, the Trojan has another option to steal data – it draws its phishing window over the attacked app. It is interesting that, in order to find out which app is on top, it uses accessibility services too.

From the information Svpeng receives from its command and control server (CnC), I was able to intercept an encrypted configuration file and decrypt it to find out the attacked apps, and to obtain a URL with phishing pages.

I uncovered a few antivirus apps that the Trojan attempted to block, and some apps with phishing URLs to overlay them. Like most mobile bankers, Svpeng overlays some Google apps to steal credit card details.

Also, the config file contained a phishing URL for the PayPal and eBay mobile apps to steal credentials and URLs for banking apps from different countries:

  • UK– 14 attacked banking apps
  • Germany – 10 attacked banking apps
  • Turkey– 9 attacked banking apps
  • Australia– 9 attacked banking apps
  • France– 8 attacked banking apps
  • Poland– 7 attacked banking apps
  • Singapore– 6 attacked banking apps

There was one more app in this configuration file – Speedway app, which is a rewards app, not a financial app. Svpeng will overlay it with a phishing window to steal credentials.

It can also receive commands from the CnC:

  • To send SMS
  • To collect info (Contacts, installed apps and call logs)
  • To collect all SMS from the device
  • To open URL
  • To start stealing incoming SMS
Distribution and protection

The Trojan-Banker.AndroidOS.Svpeng.ae is distributed from malicious websites as a fake flash player. Its malicious techniques work even on fully-updated devices with the latest Android version and all security updates installed. By accessing only one system feature this Trojan can gain all necessary additional rights and steal lots of data.

MD5

F536BC5B79C16E9A84546C2049E810E1