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
16 April, 2021
Global rank
9
Week rank
7
Month rank
8
IOCs
6793

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
3.125.223.134
3.125.102.39
18.158.249.75
3.125.209.94
181.52.110.192
192.168.100.157
79.134.225.73
3.142.129.56
78.198.121.158
82.202.167.226
52.14.18.129
3.22.53.161
3.131.207.170
13.59.15.185
13.59.15.185
79.134.225.17
3.13.191.225
185.140.53.9
193.161.193.99
192.168.100.29
Hashes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0.tcp.eu.ngrok.io
d8bfc1d6.eu.ngrok.io
majul.com
8.tcp.ngrok.io
indira8923.duckdns.org
zuletismo2.duckdns.org
sofie12.duckdns.org
tokio127.duckdns.org
electricaribe.duckdns.org
polonia783.duckdns.org
cali35.duckdns.org
duckdnw4.duckdns.org
portugal16.duckdns.org
donatelo783.duckdns.org
ongod4life.ddns.net
lachattemouilleee3875383444.duckdns.org
icecubee.ddns.net
babbyhouse90.duckdns.org
erunski22.ddns.net
u856112.nvpn.so

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