Advanced Targeted Attack Tools Found Being Used to Distribute Cryptocurrency Miners

by Cedric Pernet, Vladimir Kropotov, and Fyodor Yarochkin

Regular cybercriminals appear to be taking a page from targeted attack actors’ playbooks — or rather, toolkits — to maximize their profits from illicit activities like cryptojacking.

One of the differences between regular cybercrime and targeted attacks is intent: The former will almost always have immediate financial gain as its main motivation while the latter will have other goals, for example, intellectual property theft. Furthermore, the mindsets of the threat actors can be very different. Regular cybercriminals will typically need to think of how they can compromise as many individual devices as possible (for example, to deliver ransomware, coin miners, or banking trojans) while targeted attack threat actors will need to plan how to infiltrate and gain full access to corporate networks and remain as discreet as possible.

In addition, targeted attack campaigns often involve extensive planning as well as the creation and use of highly specialized tools. On the other hand, normal threat actors might not have the ability or resources to plan sophisticated campaigns and their tools are more generic in nature and are often available in underground markets.

However, we recently came across evidence of a large-scale cybercrime activity that appears to combine targeted attack tools and regular cybercrime: The attackers distribute typical malware such as cryptocurrency miners and ransomware by making use of sophisticated tools that were previously mostly seen in targeted attacks. In the cases we identified, the threat actors were using a package of tools from the Equation group (which was publicly leaked by the Shadow Brokers) to compromise a large number of machines running outdated versions of Microsoft Windows OS. The technique of using advanced tools to spread more ubiquitous types of malware is a trend we have been observing lately. In fact, earlier this month we found and analyzed a malware family we called BlackSquid, which made use of well-known exploits and vulnerabilities to drop a cryptocurrency miner. The findings we discuss in this entry reinforce our suspicions that entry-level cybercriminals are gaining easy access to what we can consider “military-grade” tools — and are using them for seemingly ordinary cybercrime activity.

The activity we observed involves a cybercrime campaign that targets companies across the globe to spread a cryptocurrency miner for monetary purposes. The campaign features some interesting characteristics. For one, it only targets companies — we did not find any instances of individual users being targeted. And for another, all of the compromised machines were running outdated versions of Microsoft Windows OS, still vulnerable to already patched vulnerabilities. In addition, the campaign uses Equation group tools to deliver a cryptocurrency miner to organizations around the world.

Infection and proliferation

One of the first binaries we detected on the infected machines seems to be the possible culprit of the attack — a variant of Vools (Trojan.Win32.VOOLS.SMAL01), which is an EternalBlue-based backdoor that is used to deliver cryptocurrency miners and other malware. We also found a number of other tools in the infected systems, mainly the password dumping tool Mimikatz and Equation group tools. The final payload deployed on compromised systems is a cryptocurrency miner. Using data from the Trend Micro™ Smart Protection Network™ security architecture, we can confirm that all of the compromised systems appear to be on internal segments of compromised networks.

While we could not confirm the origin of the infection, during our research we managed to find a sample that seems to be an installer which sends an HTTP request to the following server:

  • log.boreye[.]com/ipc.html?mac={MAC address}&ip={IP address}&host={host}&tick=6min&c=error_33

However, we have been unable to retrieve any miners from the URL at the time of writing. Furthermore, the site is already inactive and have possibly been migrated to a different location by the threat actors behind the attack.

We identified a common file located in the main Windows folder of all the infected machines:

  • C:\Windows\NetworkDistribution\Diagnostics.txt

The .TXT file extension used is just a trick to avoid detection. The file is in fact a ZIP archive file that contains several files (the Equation toolkit components), as shown in the image below. (Notice the presence of many familiar names such as EternalBlue and EternalChampion.) On the other hand, the DLL files, which we observed were being dropped on the target machine, match the contents of a folder in the same GitHub repository as the leak’s.

 Figure 1. The files located inside the zip archive

Figure 1. The files located inside the zip archive

All these files are freely accessible for everyone on the internet to use. Although the vulnerabilities they exploit have already been patched, they can still be used successfully on systems that have not applied the update.

The cryptocurrency miner

Since we began tracking it in March 2019, we found more than 80 different files in the wild that are involved in the campaign based on their hashes. All these files are variants of the open-source XMRig (Monero) miner, which is used at scale by numerous cybercriminals worldwide. These variants are detected as either Coinminer.Win32.MALXMR.SMBM4 or Coinminer.Win64.TOOLXMR.SMA.

Configurations from the samples we found reveal a number of mining servers such as the following:

  • coco[.]miniast[.]com:443
  • iron[.]tenchier[.]com:443
  • cake[.]pilutce[.]com:443
  • pool[.]boreye[.]com:53

Another one, though we do not have a sample, is log.miniast[.]com.

Interestingly enough, the first three domains were registered on March 17, 2019, which is the date the campaign started based on our observations. These domains were registered anonymously while the older domain boreye[.]com was registered on October 17, 2018 using an email address that has only been used to register that single domain. User credentials are needed to connect to the mining server, but only the password is needed to retrieve new hashes.

Figure 2 shows the configurations we observed with the miner binaries used by the attacker.

 Figure 2. Screenshot of the configurations used by the cryptocurrency miner binaries

Note: The passwords have been removed.

Figure 2. Screenshot of the configurations used by the cryptocurrency miner binaries

As can be seen in Figure 2, the usernames used are very similar. In addition, they all use the same password, which is a good indication that the same threat actor handles all the samples. The miner always uses the name dllhostex.exe. Furthermore, the binary is always located either in the “system32” or in the “SysWOW64” folder of the infected Windows machine, depending on the miner variant.

The targets of the campaign

The campaign seems to be widespread, with targets located in all regions of the world. Countries with large populations such as China and India also had the most number of organizations being targeted. This seems to indicate that the threat actors weren’t selective with their victims, opting for a “shotgun” method of attack, rampaging through the internal networks of compromised organizations rather than seeking out individual targets.

 Figure 3. Distribution of targeted organizations according to country

Figure 3. Distribution of targeted organizations according to country

The campaign also targeted businesses across a wide range of industries, including education, communication and media, banking, manufacturing, and technology. Again, rather than concentrate on specific industries, the attackers happen to choose targets that used obsolete or unpatched software. A large majority (roughly 83%, including all versions) of affected computers were running Windows Server 2003 SP2. This was followed by Windows 7 Ultimate Professional SP1 and Windows XP Professional.

Conclusion

While it takes some skill to deploy a large-scale campaign, it requires almost none to use tools such as the sophisticated ones leaked from the Equation group. The easy availability of these tools in the underground cybercrime markets, where ready-to-use mining servers are also being sold, allow even run-of-the-mill cybercriminals the ability to make use of them for seemingly “regular” cybercrime activity. As we discussed in our  paper entitled “Security in the Era of Industry 4.0: Dealing With Threats to Smart Manufacturing Environments,” a number of industries depend on running significantly outdated systems, rendering them vulnerable to exploits despite the fact that the vulnerabilities already have patches.

The presence of automated attack platforms and the use of lateral movement techniques in compromised infrastructure for ubiquitous threats such as cryptocurrency miners and ransomware mean that even internal networks with vulnerable systems become easy targets for cybercriminals. The campaign we discussed in this post is only one of many we have observed in recent months. It shouldn’t come as a surprise to see more instances of non-professional threat actors using professional tools to make their attacks more effective. Given what we’ve observed, we cannot stress enough the need for organizations to update their systems as soon as possible to minimize risk and prevent these kinds of threats from affecting their systems.

Trend Micro Solutions

Trend Micro endpoint solutions such as the Trend Micro Smart Protection Suites and Worry-Free™ Business Security can protect users and businesses from threats such as cryptocurrency miners by detecting malicious files and blocking all related malicious URLs. Enterprises can also monitor all ports and network protocols for advanced threats with the Trend Micro Deep Discovery™ Inspector network appliance.

Indicators of Compromise (IoCs)

Network IOCs

  • miniast[.]com:443
  • tenchier[.]com:443
  • boreye[.]com:80
  • boreye[.]com:53
  • pilutce[.]com:443

Coin miner sample hashes

SHA256 Detection
dd21a9ce1d87e3a7f9f2a592ec9dd642ca19aee4a60502c8df21d9c25f9acf86 Trojan.Win64.VOOLS.AF
2af73c8603e1d51661b0fffc09be306797558204bcbd4f95dd2dfe8363901606 Trojan.Win64.VOOLS.AB
ed2febf310ae90739002b9ddb07a29d0b2c8e92462ae4a0a6dcc19cc537ddef3 Trojan.Win64.VOOLS.AB
007f81debf1c984c5b4d5b84d6a8c06bcdf84d1a4cccdd9633e45de35015faf3 PE_VIRUX.R-3
125f93883ccccb3c33964c8bcdd17b409b53fbc44de1e3b4afd7dfe79aa358cd Coinminer.Win64.TOOLXMR.SMA
1ac26e86540610d1293c421ed05c13cd6ed51759be153c45d194ff7552c88855 Coinminer.Win64.TOOLXMR.SMA
4c3575c7b6c530603e4cd76c7dcaed12fc5ebadbf4d4d6b46352eb08458683e8 Coinminer.Win64.TOOLXMR.SMA
4e46cec7f6e7fa13c10e808f0da104a8c810b7ef17c40d0e9a908453be87e7f4 Coinminer.Win64.TOOLXMR.SMA
5472f9ba3bc623450cc208669dacddb1b6a73ffe4dc705b85cf41637070fda28 Coinminer.Win64.TOOLXMR.SMA
572c3943f70a3e362d9bf195ce37cec68074235eb1abba9f0cdbb91f5231a572 Coinminer.Win64.TOOLXMR.SMA
5db45fa654910495592cf1ca00d7ef537708c38c4803d10d89eaa0ddba0e7d8c Coinminer.Win64.TOOLXMR.SMA
6ee5c5724ecc70f77aadcf00c77829e5313f44c61b2720113ada0c8263ac662c Coinminer.Win64.TOOLXMR.SMA
7ced0990ac94f36fab21821395f543f3a06be486c9f34cdc137874912573fb27 Coinminer.Win64.TOOLXMR.SMA
7f5bddeb0c9ecde4d64ddac8b046859fb1627811d96c29dfa2b88102740571ce Coinminer.Win64.TOOLXMR.SMA
94af094fc02cfe85a80f2f90d408f9598f9d77def36155e16a90e2bd8f8fdcce Coinminer.Win64.TOOLXMR.SMA
975dc8ecda9a9c15d19c4d9d67f961366d2f0ac1074b5eb5d3b36e653092a6a3 Coinminer.Win64.TOOLXMR.SMA
bafe63e8fd76f1c9010137e6cd5137655ea12ab5c25d0b86700627b2ebad2be0 Coinminer.Win64.TOOLXMR.SMA
ce5025a484b3e2481e248dee404e6d321b6d7f58bae77b284ec9e602672e6a10 Coinminer.Win64.TOOLXMR.SMA
ce8cb7c8dc29b9e4feab463fdf53b569b69e6a5c4ab0e50513b264563d74a6ac Coinminer.Win64.TOOLXMR.SMA
9af55d177e7d7628dc63f7753de4780031073098e1c674e619826cb97c190744 Coinminer.Win64.TOOLXMR.AR
f81dd3e5b0507d78815f5909ab442545cb3f5262397abd89b5947e1e7b3fef12 Coinminer.Win64.TOOLXMR.AQ
35d10df58e340b6a7d69e590852b84a6a02f774306c3eb29e60e6b24740456eb Coinminer.Win32.MALXMR.SMBM4
13800d1075e56f9bd0d87b2e85555040233e8b2ec679770101d046ffa4e39582 Coinminer.Win32.MALXMR.SMBM4
199e0419622e108ffdd7c9de571931d9aedc4f980a602766c0fdcb17bdddfc2a Coinminer.Win32.MALXMR.SMBM4
1bc9762470423393521d9aa64d505501d201d3cb50c8e6576d4381590b090d75 Coinminer.Win32.MALXMR.SMBM4
2d6a5eb8a78cddee8ce90321aab80f85784b11a87b00fde75c4c457998a5aebd Coinminer.Win32.MALXMR.SMBM4
3638ee8c0153b2763eb36246d9ffe4f7ec6d1f7e76876fb6f579c45e6e55e260 Coinminer.Win32.MALXMR.SMBM4
469e7ac4b5bad89e305e1e7ec65773844f3d639e84476da4b1fdf442a7c28504 Coinminer.Win32.MALXMR.SMBM4
59e3cf8f342a2bb5ce22bb03f8671568f68751f807002f9b329ed58e12a8831c Coinminer.Win32.MALXMR.SMBM4
5cd9ff29454e84923d4178484ecfb3bc48561d4401fa94b98f9d2693d47a740a Coinminer.Win32.MALXMR.SMBM4
6173542183c304ac2efc0348df799c1e3dea508cceaaac461bd509dc436d4edf Coinminer.Win32.MALXMR.SMBM4
82c0b0fbb0f44ad2bc46c8b105f167f0feadf936ff811f97aab3a9a6cccc2fb2 Coinminer.Win32.MALXMR.SMBM4
87488d9ad54b88e5488c18d8de6a338eaf4fe7bdeec2df7eeaf90380de1533b6 Coinminer.Win32.MALXMR.SMBM4
8d402a3871bada94d84dd8a7c29361f27b75ac37394f6de059b06afb340fe3d6 Coinminer.Win32.MALXMR.SMBM4
9853e7bd0906cf92d2767fa55ee0a645f23099b37d59654d3c388d897a19fb1e Coinminer.Win32.MALXMR.SMBM4
af21fb86d48b60ee58084570fba12cf3dbc3992c713421a265cd451c169967d2 Coinminer.Win32.MALXMR.SMBM4
cf60518d2a22631d0539964ff97bc396b44ef5f6979f7a9e59e03c89598db0bf Coinminer.Win32.MALXMR.SMBM4
ec85ec44771401d4a71cb7f8bc3597d55ec02b84178464ab33161c77c4f51f0b Coinminer.Win32.MALXMR.SMBM4
ecfcd390712f6ac57b822ef519063f8e9151e90549e245e4e2a70d02ff584634 Coinminer.Win32.MALXMR.SMBM4

 

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Story added 13. June 2019, content source with full text you can find at link above.