Remcos

Remcos is a RAT type malware which means that attackers use it to perform actions on infected machines remotely. This malware is extremely actively caped up to date with updates coming out almost every single month.

Type
Trojan
Origin
ex-USSR territory
First seen
1 June, 2016
Last seen
13 July, 2020
Global rank
11
Week rank
10
Month rank
10
IOCs
3885

What is Remcos trojan?

Remcos is a remote access trojan – a malware used to take remote control over infected PCs. It has been operational since 2016 when it first became available for sale in the underground hacker communities on the dark web.

Remcos RAT has been receiving substantial updates through its lifetime. In fact, this malware is being maintained extremely actively with new releases coming out almost every month. In April 2019 the malware was available for purchase for as little as just over 60 dollars up to over 400 dollars depending on the selected package.

General description of Remcos trojan

This Trojan is created and sold to clients by a “business” called Breaking Security. Although Breaking Security promises that the program is only available to those who intend to use it for legal purposes, in reality, Remcos RAT gives clients all necessary features to launch potentially destructive attacks. The malware can be purchased with different cryptocurrencies. The program is able to remotely control PCs with any Windows OS including XP and newer. It can also capture screenshots and record keystrokes on infected machines.

What’s more, it comes equipped with a cryptor program that enables the malware to stay hidden from antivirus software. In fact, Breaking Security has released a video on its YouTube channel which demonstrates how multiple antiviruses fail to detect the presence of Remcos. In addition, Breaking Security provides attackers with a keylogger that can be used to remotely record keystrokes of the victim, a mass mailer program that can be used to carry out distribution campaigns and a DynDNS service. With all additional services connected, purchasers gain all they need to create their own functioning botnets.

The company responsible for selling Remcos RAT to the criminals is registered in Germany. Germany is the only country out of all European Union members which do not allow to look up company details online, therefore founders of Breaking Security are still not identified. The website itself does not provide any information about the company or about the team behind Remcos. The domain name of the website itself is hosted on Cloudflare and all information related to it is protected by the privacy policy of the hoster organization. Clearly, the people behind Breaking Security have taken a lot of effort to stay anonymous.

Remcos malware analysis

Remcos RAT execution can be watched in-depth in a video recorded in the ANY.RUN malware hunting service.

process graph of the Remcos execution Figure 1: Displays the lifecycle of Remcos as presented by a visual graph generated by ANY.RUN

text report 0f the Remcos trojan analysis Figure 2: A customizable text report generated by ANY.RUN is a feature specifically developed to simplify the sharing of research results.

Remcos trojan execution process

Remcos trojan can be delivered in different forms. For instance, it can be spread as an executable file with the name that should convince users to open it or it pretends to be a Microsoft Word file that exploits vulnerabilities to download and execute the main payload. In our simulation, after Remcos made its way to infect the device and begin the execution process, it started VBS script execution. Script run command line and proceeded to drop an executable file from it. This file was the main payload and it carried out the main malicious activities - stealing information, changing the autorun value in the registry and connecting to the C2 server.

remcos execution process tree Figure 3: Execution processes of Remcos as displayed by the ANY.RUN malware analysis service

Distribution of Remcos

Although being distributed using multiple methods, being provided in a bundle with mass mailer software, Remcos RAT usually gets into victims’ machines through malicious attachments in spam email campaigns. The attackers normally use phishing techniques to try and trick users into downloading file attachments, commonly – contaminated Microsoft Office files. Once downloaded, the files would prompt the users to activate macros which are required for the execution of Ramcos to start.

Attackers who utilize this Trojan are known to target specific organizations and sometimes go a long way to craft custom phishing emails designed to fool their victims. Corporations that are known to become targets of Remcos attacks include news agencies and businesses energy industry-related businesses.

If the victim does enable the macros, they reconstruct a small executable file which is then dropped to a pre-specified location and launched from there. Even though the location can vary from sample to sample, it usually includes one of the following locations, typical for malware creators: %APPDATA% and %TEMP%. This file then proceeds to download the main payload, which is Remcos itself, from a control server and then being the execution process.

How to detect Remcos using ANY.RUN?

Since Remcos trojan creates log files without encryption analysts can take a look at it. Open either "Files" tab in the lower part of the task's window or click on the process and then on the button "More Info" in the appeared window. After that, all you need to do is just click on the logs.dat file. If you see strings like on the illustration below you can be sure it Remcos.

remcos log file Figure 4: Remcos log file

Conclusion

Remcos RAT is a dangerous trojan available to attackers for a relatively inexpensive price. Despite its accessibility, it comes equipped with enough robust features to allow attackers to set up their own effective botnets. What's more, it is modernized with updates that are being released nearly every month by the owner company. Accessibility and powerful feature set helped to make Ramcos into a powerful and dangerous trojan.

Thankfully, malware hunting services such as ANY.RUN gives professionals an equally robust feature set to research threats like Ramcos and respond with effective countermeasures.

IOCs

IP addresses
193.161.193.99
185.244.30.19
185.19.85.135
192.169.69.25
213.152.161.20
3.20.98.123
3.137.63.131
79.134.225.49
103.147.184.53
185.140.53.219
3.126.37.18
185.165.153.17
185.19.85.183
109.169.89.116
181.48.139.42
79.134.225.29
79.134.225.75
185.140.53.91
185.244.30.252
79.134.225.72
Hashes
e2db5085b7216e4bd5f200ca3a57475b990777c5948ade7582786ae2d7c80843
dfa62653c2606c14be6b244fdc19c07c2d31fe4553f2cebba08c972e92f27434
1c964f7b4a1f588cab0f3a68eb987905b9d5b4d3121db07af0e26b291db6f1b7
d69aa1932b2e702e5065ee19da9fc9cf2b05e7dbaa617141b14eaa501a14955e
fa4a8005816d24492d1bc2ed37d4d4c4b318527ca00c12bce4a9d67691d89695
6394fec7797de69f3c7bca0c87e57370c6776694826815f6d4a4c3479321a2ed
4e1d3b8c768a94cac9b1cf78465a94286f711e4a190a5d3bc6a1757a397f74f1
d7edec42151eb4762b265be6014bd7f391c948406a46a9f997337e2b80424193
8164bb94001b99694b96e7b79d2e319971474ea27e30a7529d1864de1f7e3c2a
b297513b7c765c99a86cb9f5ce6f67e3d8dcc3c677b5ff5df4ad41c4c7c832a0
7210f2ca290296d1f6e61da4b3192ad19afd719d6cf77dbb2d6810734b349826
6d1493af16375625493ed87ebe818ffc90123035cc972d8f362d821641a2ab29
89de99e8cfb9adc63e6b73cc1ca21757373ecd4ee31d28483cff8fd1f6e6f046
57764ed145ae729a887555a6e0c9017d40b23ddd64498dec5f2830547ee83ea7
6df94b7fa33f1b87142adc39b3db0613fc520d9e7a5fd6a5301dd7f51f8d0386
cb004227c7c2ad4bedaff4efb12b46c5131317e2ea46e6316e916ee703a19329
978a4093058aa2ebf05dc353897d90d950324389879b57741b64160825b5ec0e
f774107985f64b0ecfea0e5c6def9fbd555b8f9819544969daf602fd51f24d13
79942eb4e42a57cc1f8a5b3ac7630fd81c923fbff23eb263df55386c4823408b
5c9667b60610ff2eeb6b26096b7ac951ed3d59fc716a6b8aa1c94c38658b0db7
Domains
portababy-24207.portmap.host
Jqzzo-50729.portmap.host
SkidDuality-21146.portmap.host
ChrisLad-61434.portmap.host
xSkewber-24412.portmap.host
dexxxy-35719.portmap.host
Lyhr0x-37951.portmap.host
toxob-52623.portmap.host
patheticworm-59180.portmap.host
screechy-35254.portmap.host
DJTeddyBear0-61476.portmap.io
TyroneJamallkins-24046.portmap.host
steen-46861.portmap.host
dududjh-25087.portmap.host
NonameME-32892.portmap.host
tester894-32062.portmap.io
v3-56445.portmap.host
Bigpp1234-23204.portmap.host
DannyJanny-46342.portmap.io
DeeJay140-28261.portmap.io

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