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BlackEnergy APT Attacks in Ukraine employ spearphishing with Word documents

Thu, 01/28/2016 - 06:01

Late last year, a wave of cyber-attacks hit several critical sectors in Ukraine. Widely discussed in the media, the attacks took advantage of known BlackEnergy Trojans as well as several new modules.

BlackEnergy is a Trojan that was created by a hacker known as Cr4sh. In 2007, he reportedly stopped working on it and sold the source code for an estimated $700. The source code appears to have been picked by one or more threat actors and was used to conduct DDoS attacks against Georgia in 2008. These unknown actors continued launching DDoS attacks over the next few years. Around 2014, a specific user group of BlackEnergy attackers came to our attention when they began deploying SCADA-related plugins to victims in the ICS and energy sectors around the world. This indicated a unique skillset, well above the average DDoS botnet master.

For simplicity, we’re calling them the BlackEnergy APT group.

One of the prefered targets of the BlackEnergy APT has always been Ukraine. Since the middle of 2015, one of the preferred attack vectors for BlackEnergy in Ukraine has been Excel documents with macros that drop the Trojan to disk if the user chooses to run the script in the document.

A few days ago, we discovered a new document that appears to be part of the ongoing BlackEnergy APT group attacks against Ukraine. Unlike previous Office files used in previous attacks, this is not an Excel workbook, but a Microsoft Word document. The lure used a document mentioning the Ukraine “Right Sector” party and appears to have been used against a television channel.

Introduction

At the end of the last year, a wave of attacks hit several critical sectors in Ukraine. Widely discussed in the media and by our colleagues from ESET, iSIGHT Partners and other companies, the attacks took advantage of both known BlackEnergy Trojans as well as several new modules. A very good analysis and overview of the BlackEnergy attacks in Ukraine throughout 2014 and 2015 was published by the Ukrainian security firm Cys Centrum (the text is only available in Russian for now, but can be read via Google Translate).

In the past, we have written about BlackEnergy, focusing on their destructive payloads, Siemens equipment exploitation and router attack plugins. You can read blogs published by my GReAT colleagues Kurt Baumgartner and Maria Garnaeva here and here. We also published about the BlackEnergy DDoS attacks.

Since mid-2015, one of the preferred attack vectors for BlackEnergy in Ukraine has been Excel documents with macros which drop the trojan to disk if the user chooses to run the script in the document.

For the historians out there, Office documents with macros were a huge problem in the early 2000s, when Word and Excel supported Autorun macros. That meant that a virus or trojan could run upon the loading of the document and automatically infect a system. Microsoft later disabled this feature and current Office versions need the user to specifically enable the Macros in the document to run them. To get past this inconvenience, modern day attackers commonly rely on social engineering, asking the user to enable the macros in order to view “enhanced content”.

Few days ago, we came by a new document that appears to be part of the ongoing attacks BlackEnergy against Ukraine. Unlike previous Office files used in the recent attacks, this is not an Excel workbook, but a Microsoft Word document:

“$RR143TB.doc” (md5: e15b36c2e394d599a8ab352159089dd2)

This document was uploaded to a multiscanner service from Ukraine on Jan 20 2016, with relatively low detection. It has a creation_datetime and last_saved field of 2015-07-27 10:21:00. This means the document may have been created and used earlier, but was only recently noticed by the victim.

Upon opening the document, the user is presented with a dialog recommending the enabling of macros to view the document.

Interestingly, the document lure mentions “Pravii Sektor” (the Right Sector), a nationalist party in Ukraine. The party was formed in November 2013 and has since played an active role in the country’s political scene.

To extract the macros from the document without using Word, or running them, we can use a publicly available tool such as oledump by Didier Stevens. Here’s a brief cut and paste:

As we can see, the macro builds a string in memory that contains a file that is created and written as “vba_macro.exe”.

The file is then promptly executed using the Shell command.

The vba_macro.exe payload (md5: ac2d7f21c826ce0c449481f79138aebd) is a typical BlackEnergy dropper. It drops the final payload as “%LOCALAPPDATA%\FONTCACHE.DAT”, which is a DLL file. It then proceeds to run it, using rundll32:

rundll32.exe “%LOCALAPPDATA%\FONTCACHE.DAT”,#1

To ensure execution on every system startup, the dropper creates a LNK file into the system startup folder, which executes the same command as above on every system boot.

%APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\{D0B53124-E232-49FC-9EA9-75FA32C7C6C3}.lnk

The final payload (FONTCACHE.DAT, md5: 3fa9130c9ec44e36e52142f3688313ff) is a minimalistic BlackEnergy (v3) trojan that proceeds to connect to its hardcoded C&C server, 5.149.254.114, on Port 80. The server was previously mentioned by our colleagues from ESET in their analysis earlier this month. The server is currently offline, or limits the connections by IP address. If the server is online, the malware issues as HTTP POST request to it, sending basic victim info and requesting commands.

The request is BASE64 encoded. Some of the fields contain:

  • b_id=BRBRB-…
  • b_gen=301018stb
  • b_ver=2.3
  • os_v=2600
  • os_type=0

The b_id contains a build id and an unique machine identifier and is computed from system information, which makes it unique per victim. This allows the attackers to distinguish between different infected machines in the same network. The field b_gen seems to refer to the victim ID, which in this case is 301018stb. STB could refer to the Ukrainian TV station “STB”, http://www.stb.ua/ru/. This TV station has been publicly mentioned as a victim of the BlackEnergy Wiper attacks in October 2015.

Conclusions

BlackEnergy is a highly dynamic threat actor and the current attacks in Ukraine indicate that destructive actions are on their main agenda, in addition to compromising industrial control installations and espionage activities.

Our targeting analysis indicates the following sectors have been actively targeted in recent years. If your organization falls into these categories, then you should take BlackEnergy into account when designing your defences:

  • ICS, Energy, government and media in Ukraine
  • ICS/SCADA companies worldwide
  • Energy companies worldwide

The earliest signs of destructive payloads with BlackEnergy go back as far as June 2014. However, the old versions were crude and full of bugs. In the recent attacks, the developers appear to have gotten rid of the unsigned driver which they relied upon to wipe disks at low level and replaced it with more high level wiping capabilities that focus on file extensions as opposed on disks. This is no less destructive than the disk payloads, of course, and has the advantage of not requiring administrative privileges as well as working without problems on modern 64-bit systems.

Interestingly, the use of Word documents (instead of Excel) was also mentioned by ICS-CERT, in their alert 14-281-01B.

It is particularly important to remember that all types of Office documents can contain macros, not just Excel files. This also includes Word, as shown here and alerted by ICS-CERT and PowerPoint, as previously mentioned by Cys Centrum.

In terms of the use of Word documents with macros in APT attacks, we recently observed the Turla group relying on Word documents with macros to drop malicious payloads (Kaspersky Private report available). This leads us to believe that many of these attacks are successful and their popularity will increase.

We will continue to monitor the BlackEnergy attacks in Ukraine and update our readers with more data when available.

More information about BlackEnergy APT and extended IOCs are available to customers of Kaspersky Intelligence Services. Contact intelreports@kaspersky.com.

Kaspersky Lab products detect the various trojans mentioned here as: Backdoor.Win32.Fonten.* and
HEUR:Trojan-Downloader.Script.Generic.

To know more about countering BlackEnergy and similar offensives, read this article on Kaspersky Business Blog.

Indicators of compromise Word document with macros (Trojan-Downloader.Script.Generic):

e15b36c2e394d599a8ab352159089dd2

Dropper from Word document (Backdoor.Win32.Fonten.y):

ac2d7f21c826ce0c449481f79138aebd

Final payload from Word document (Backdoor.Win32.Fonten.o):

3fa9130c9ec44e36e52142f3688313ff

BlackEnergy C&C Server:

5.149.254[.]114

The Asacub Trojan: from spyware to banking malware

Wed, 01/20/2016 - 06:02

We were recently analyzing a family of mobile banking Trojans called Trojan-Banker.AndroidOS.Asacub, and discovered that one of its C&C servers (used, in particular, by the earliest modification we know of, as well as by some of the more recent ones) at chugumshimusona[.]com is also used by CoreBot, a Windows spyware Trojan. This prompted us to do a more detailed analysis of the mobile banking Trojan.

The earliest versions of Asacub that we know of emerged in the first half of June 2015, with functionality that was closer to that of spyware Trojans than to banking malware. The early Asacub stole all incoming SMS messages regardless of who sent them, and uploaded them to a malicious server. The Trojan was capable of receiving and processing the following commands from the C&C:

  • get_history: upload browser history to a malicious server;
  • get_contacts: upload list of contacts to a malicious server;
  • get_listapp: upload a list of installed applications to a malicious server;
  • block_phone: turn off the phone’s screen;
  • send_sms: send an SMS with a specified text to a specified number.

New versions of Asacub emerged in the second half of July 2015. The malicious files that we are aware of used the logos of European banks in their interface, unlike the early versions of the Trojan, which used the logo of a major US bank.

There was also a dramatic rise in the number of commands that Asacub could execute:

  • get_sms: upload all SMSs to a malicious server;
  • del_sms: delete a specified SMS;
  • set_time: set a new time interval for contacting the C&C;
  • get_time: upload the time interval for contacting the C&C to the C&C server;
  • mute_vol: mute the phone;
  • start_alarm: enable phone mode in which the device processor continues to run when the screen goes blank;
  • stop_alarm: disable phone mode in which the device processor continues to run when the screen goes blank;
  • block_phone: turn off the phone’s screen;
  • rev_shell: remote command line that allows a cybercriminal to execute commands in the device’s command line;
  • intercept_start: enable interception of all incoming SMSs;
  • intercept_stop: disable interception of all incoming SMSs.

One command that was very unusual for this type of malware was rev_shell, or Reverse shell, a remote command line. After receiving this command, the Trojan connects a remote server to the console of the infected device, making it easy for cybercriminals to execute commands on the device, and see the output (results) of those commands. This functionality is typical of backdoors and very rarely found in banking malware – the latter aims to steal money from the victim’s bank account, not control the device.

The most recent versions of Asacub – detected in September 2015 or later – have functionality that is more focused on stealing banking information than earlier versions. While earlier versions only used a bank logo in an icon, in the more recent versions we found several phishing screens with bank logos.

One of the screenshots was in Russian and was called ‘ActivityVTB24’ in the Trojan’s code. The name resembles that of a large Russian bank, but the text in the screen referred to the Ukrainian bank Privat24.

Phishing screens were present in all the modifications of Asacub created since September that are known to us, but only the window with bank card entry fields was used. This could mean that the cybercriminals only plan to attack the users of banks whose logos and/or names they use, or that a version of Asacub already exists that does so.

After launching, the ‘autumnal version’ of the Trojan begins stealing all incoming SMSs. It can also execute the following commands:

  • get_history: upload browser history to a malicious server;
  • get_contacts: upload list of contacts to a malicious server;
  • get_cc: display a phishing window used to steal bank card data;
  • get_listapp: upload a list of installed applications to a malicious server;
  • change_redir: enable call forwarding to a specified number;
  • block_phone: turn off the phone’s screen;
  • send_ussd: run a specified USSD request;
  • update: download a file from a specified link and install it;
  • send_sms: send an SMS with a specified text to a specified number.

Although we have not registered any Asacub attacks on users in the US, the fact that the logo of a major US bank is used should serve as a warning sign. It appears the Trojan is developing rapidly, and new dangerous features, which could be activated at any time, are being added to it.

As for the relationship between Asacub and the Corebot Trojan, we were unable to trace any link between them, except that they share the same C&C server. Asacub could be Corebot’s mobile version; however, it is more likely that the same malicious actor purchased both Trojans and has been using them simultaneously.

Asacub today

Very late in 2015, we discovered a fresh Asacub modification capable of carrying out new commands:

  • GPS_track_current – get the device’s coordinates and send them to the attacker;
  • camera_shot – take a snapshot with the device’s camera;
  • network_protocol – in those modifications we know of, receiving this command doesn’t produce any results, but there could be plans to use it in the future to change the protocol used by the malware to interact with the C&C server.

This modification does not include any phishing screens, but banks are still mentioned in the code. Specifically, the Trojan keeps attempting to close the window of a certain Ukrainian bank’s official app.

Code used to close a banking application

In addition, our analysis of the Trojan’s communication with its C&C server has shown that it frequently gets commands to work with the mobile banking service of a major Russian bank.

During the New Year holidays, the new modification was actively distributed in Russia via SMS spam. In just one week, from December 28, 2015 to January 4, 2016, we recorded attempts to infect over 6,500 unique users. As a result, the Trojan made the Top 5 most active malicious programs. After that, the activity of the new Asacub modification declined slightly. We continue to follow developments related to this malware.

Targeted Mobile Implants in the Age of Cyber-Espionage

Mon, 01/18/2016 - 05:57

Background

When mass-produced electronic spying programs became widely known by the public, many email providers, businesses, and individuals started to use data encryption. Some of them have implemented forced encryption solutions to server connections, while others went further and implemented end-to-end encryption for data transmission as well as server storage.

Unfortunately, albeit important, said measures did not solve the core problem. Well, the original architectural design used in emails allows for metadata to be read as plain text on both sent and received messages. Said metadata includes recipient, sender, sent/receipt date, subject, message size, whether there are attachments, and the email client used to send out the message, among other data.

This information is enough for someone behind targeted campaigns attacks to reconstruct a time line for conversations, learn when people communicate with one another, what they talk about, and how often they communicate. Using this information to fill in the gaps, threat actors are able to learn enough about their targets.

In addition to the above, technologies are evolving, so something that is encrypted today may be easily decrypted a few years later, sometimes only months later, depending on how strong the encryption key is and how fast technologies are developing.

Said scenario has made people move away from email exchanges when it comes to confidential conversations. Instead, they started using secure mobile messaging applications with end-to-end encryption, no server storage and timed deletion. On the one hand, these applications manage strong data and connection encryptions. On the other hand, they manage auto deletion on cell phones and provider servers. Finally, they practically have no metadata or are impersonal, thus not allowing identifiers about targets or data correlation. This way, conversations are truly kept confidential, safe, and practical.

Naturally, this scenario has made threat actors develop implants for mobile devices since, from a hacking perspective, they address all the aforementioned technical limitations―that is, the inability to intercept conversations between users who have migrated to these secure mobile messaging applications. What is an implant? This is an interesting terminology invented by the very same threat actors behind targeted attacks. We saw it for the first time during the Careto campaign we announced a few years ago.

Now we will analyze some implants developed by HackingTeam to infect mobile devices running on iOS (Apple), Android, Blackberry, and Windows Mobile. HackingTeam isn’t the only group developing mobile implants. There are several campaigns with different roots, which have been investing in the development of mobile malware and used it in targeted attacks at the regional and international level.

Implants for Androids

Android-based phones are more affordable and, consequently, more popular worldwide. That is why threat actors responsible for targeted attacks have Android phones as their #1 priority and have developed implants for this operating system in particular.

Let’s analyze what one of these implants is capable of.

HEUR:Trojan-Spy.AndroidOS.Mekir.a

It is well known that the encryption algorithm used in text messages is weak. It is safe to assume that practically all text messages sent are susceptible to interception. That is precisely why many users have been using instant messaging programs. In the coding fragment above, we can see how threat actors are able to obtain access to the messaging database used by WeChat, a mobile application for text message exchange.

Let’s assume that the messaging application being used by the victim is really secure and has applied a strong end-to-end encryption, but all messages sent and received are stored locally. In said case, threat actors would still have the ability to decode these messages. Well, when they steal a database along with the encryption key that is stored within the victim’s device, threat actors behind these attacks can decrypt all contents. This includes all database elements, not only the text information, but also geographic locations shared, pictures, files, and other data.

Besides, threat actors have the ability to manipulate the camera on the device. They can even take pictures of the victim for identity confirmation. This also correlates with other data, such as the wireless network provider that the phone is connected to.

Actually, it doesn’t matter what application the victim is using. Once the mobile end point is infected, threat actors are able to read all messages sent and received by the victim. In the following code segments, we can see the instructions used to interact with messaging applications Viber and WhatsApp.

If a mobile devices is compromised with an implant, the rule becomes very simple – if you read a secure text message on your screen, the threat actor behind that implant, reads it too.

Implants for iOS

Undoubtedly, Apple mobile devices also enjoy a large market share. In some markets, they are certainly more popular than Android devices.

Apple has managed the safety architecture of its devices very well. However, it doesn’t make them completely immune to malware attacks, especially when there are high-profile threat actors involved.

There are several infection vectors for these devices. Likewise, when high-profile targets are selected, threat actors behind these targeted attacks may apply infection techniques that use exploits whose costs are higher―hundreds of thousands of dollars―but highly effective, as well. When targets are of an average profile, less sophisticated, but equally effective infection techniques are used. For example, we would point to malware installations from a previously infected computer when a mobile device is connected through a USB port.

What technical abilities do iOS implants have? Let’s see the following implant example:

Trojan.OSX.IOSInfector.a

This Trojan infects iOS devices as they are being charged by the victim of the attack by using a previous Jailbreak made to the device. In other words, if targets usually charge their cell phones using a USB cable, the pre-infected computer may force a complete Jailbreak on the device and, once the process is complete, the aforementioned implant is installed.

In this code, you can see that the attacker is able to infected the device and confirm the victim’s identity. This is a crucial step during targeted attacks, since threat actors behind this kind of attacks wouldn’t want to infect the wrong victim and―worse yet―lose control of their implant and spoil the entire operation, thus exposing their attack to the public.

Consequently, one of the technical abilities of these implants is to verify the phone number of their victim, along with other data to make sure they’re not targeting the wrong person.

Among other preliminary surveying actions, this implant also verifies the name of the mobile device and the exact model, battery status, Wi-Fi connection data, and the IMEI number, which is unique to each device.

Why would they check the battery status? Well, there are several reasons for that, the main one of them being that data can be transferred through the internet to the hacker’s server as this information is extracted from an infected device. When phones are connected to the internet, be it through a data plan or Wi-Fi connection, the battery drains faster than normal. If threat actors extract data at an unsuitable moment, the victim could easily notice that there’s something wrong with the phone, since the battery would be hot and start draining faster than normal. That is the reason why threat actors would rather extract information from victims―especially heavy data like photos or videos―at a moment when their battery is being charged and the cell phone is connected to the Wi-Fi.

A key part of spying techniques is to combine a victim’s real world with the digital world they live in. In other words, the objective is not only to steal information stored in the cell phone, but also to spy conventional conversations carried out off line. How do they do it? By enabling the front camera and microphone on hacked devices. The problem is that, if the cell phone isn’t in silent or vibrate mode, it will make a particular sound as a picture is taken with the camera. How to resolve it? Well, implants have a special setting that disables camera sounds.

Once the victim is confirmed, the hacker once again starts to compile the information they are interested in. The coding below shows that threat actors are interested in the Skype conversations their victims are having.

This way, threat actors have complete control over their victims’ conversations. In this example, Skype is the messaging application being used by threat actors, but it could actually be any application of their choice, including those considered very secure apps. As mentioned above, the weakest link is the mobile end point and, once it is compromised, there is no need to even crack any encryption algorithm, no matter how strong it may be.

Implants for Blackberry

Some targets may use Blackberry phones, which are known to be one of the most secure operating systems in the market. Even though they are safer, threat actors behind targeted attacks don’t lag behind and they have their arsenal ready.

Trojan-Spy.BlackberryOS.Mekir.a

This implant is characterized by a strong code obfuscation technique. Analyzing it is complex task. When we look at the code, we can clearly see that even though the implant comes from the same threat actor, the developer belongs to another developer group. It’s as if a specific group were in charge of developing implants for this operating system in particular.

What actions may these implants develop in an infected Blackberry device? Well, there are several possible actions:

  • Checking the Battery Status
  • Tracking the victim’s geographic location
  • Detecting when a SIM card is replaced
  • Reading text messages stored within the device
  • Compiling a list of calls made and received by the device.

Once Blackberry phones start to use the Android operating system, threat actors will have a farther-reaching operation.

Implants for Windows Mobile

Windows Mobile aren’t necessarily the most popular operating system for mobile devices in the market, but it is the native OS used by Nokia devices, which are preferred by people looking for quality and a solid track history. There is a possibility that some targets may use this operating system, and that is why the development of implants for Windows Mobile devices is underway as well. Next, we will see the technical scope of implants for Windows Mobile devices.

HEUR:Trojan-Spy.WinCE.Mekir.a

When infecting a victim’s mobile device, this implant is hidden under a dynamic library file by the name bthclient.dll, which is supposedly a Bluetooth driver.

The technical abilities of these implants are practically limitless. Threat actors may develop several actions, such as checking:

  • A list of apps installed,
  • The name of the Wi-Fi access point to which the victim is connected,
  • Clipboard content that usually contains information of interest to the victim and, consequently, to the attacker.

Threat actors may even be able to learn the name of the APN that victims connect to while using the data plan through their provider.

Additionally, threat actors can actively monitor specific applications, such as the native email client and communications hub being used by a Windows Mobile device to process the victim’s communication data.

Conclusions

Considering the explanation in the introduction, it is probable that the most sensitive conversations take place in secure end-to-end mobile applications and not necessarily emails sent with PGP. Threat actors are aware of it, and that is why they have been actively working not only on developing implants for desktop computers, but also for mobile devices. We can say for sure that threat actors enjoy multiple benefits when they infect a mobile device, instead of a traditional computer. Their victims are always carrying their cell phones with them, so these devices contain information that their work computers won’t. Besides, mobile devices are usually less protected from a technological point of view, and victims oftentimes don’t believe their cell phones could ever become infected.

Despite a strong data encryption, a compromised mobile end point is completely exposed to spying, since threat actors have the same ability to read messages as users themselves. Threat actors don’t need to struggle with encryption algorithms, nor intercept data at the network layer level. They simply read this information the same way, as their victim would.

Mobile implants don’t belong to the group of massive attacks launched by cybercriminals; they are actually targeted attacks in which victims are carefully selected before the attack. What Makes You A Target?

There are several factors involved in being a target, including whether you are a politically exposed person, have contacts of interest to threat actors, are working on a secret or sensitive project that is also of interest, among others. One thing is certain: if you’re targeted by such an attack, the probability of infection is very high.

Everything we’re seeing now is a battle for numbers. You cannot decide whether you’ll become a victim, but one thing you could do is elevate the cost of such an attack to the point that threat actors might give up and move on to a less expensive target who is more tangible in terms of time invested and risk of the exploit campaign being discovered. How Can Someone Elevate the Cost of an Attack? Here is a set of best practices and habits in general. Each case is unique, but the main idea is to make threat actors lack motivation once it becomes too laborious to carry out their operation, thus increasing their risk of failure.

Among the basic recommendations to improve the security of our mobile devices, we could highlight the following:

  • Always use a VPN connection to connect to the Internet. This will help making your network traffic not easily interceptable and susceptible to malware that could be directly injected into a legitimate application being downloaded from the internet.
  • Do not charge your mobile devices using a USB port connected to a computer. The best thing you can do is to plug your phone directly into the AC power adapter.
  • Install an anti-malware program. It has to be the best one. It seems that the future of these solutions lies precisely in the same technologies already implemented for desktop security: Default Deny and Whitelisting.
  • Protect your devices with a password, not a PIN. If the PIN is found, threat actors may gain physical access to your mobile device and install the implant without your knowledge.
  • Use encryption in the data storage memories implemented by your mobile devices. This advice is especially current for devices that allow for memory disks extraction. If threat actors extract your memory by connecting it to another device, they’ll also be able to easily manipulate your operating system and your data in general.
  • Do NOT Jailbreak your device, especially if you’re not very sure what it implies.
  • Don’t use second-hand cell phones that may already come with pre-installed implants. This piece of advice is especially important if your cell phone comes from someone you’re not very familiar with.
  • Always keep the operating system in your mobile device updated and install the latest upgrade as soon as it becomes available.
  • Review all processes being executed in your device memory.
  • Review all authorized apps in your system and disable the automatic data submission function for logs and other service data, even if the communication is between your cell phone and your provider.
  • Finally, keep in mind that, without a doubt, conventional conversations in a natural environment are always safer than those carried out electronically.