Remcos

Remcos is a RAT type malware that attackers use 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
5 October, 2022
Global rank
9
Week rank
12
Month rank
10
IOCs
16639

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 throughout 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 can remotely control PCs with any Windows OS, including XP and newer. It can also capture screenshots, record keystrokes on infected machines, and send the collected information to host servers.

What’s more, it comes equipped with a crypto 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 the analysis of 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 a client-server connection. With all additional services combined, 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 that do not allow looking 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 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 and analysis can be watched in-depth in a video recorded in the ANY.RUN malware hunting service. Moreover, you can also research other malicious families there such as AZORult and Adwind.

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. Based on RAT's analysis, 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, obfuscate the server component. In our simulation, after Remcos made its way to infect the device and begin the execution process, it started VBS script execution. Script ran 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, the analysis proves that 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 the macros 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. This file then proceeds to download the main payload, which is Remcos itself, from a control server and then begin the execution process. 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%.

How to detect Remcos using ANY.RUN?

Cybersecurity specialists can easily detect Remcos – the trojan writes its name into a registry. Look at registry events: click on the process and then on the More Info button. If the Registry changes tab has a key like "HKEY_CURRENT_USER\Software\Remcos-{digits_letters}", you can be sure it’s Remcos.

remcos log file Figure 4: Remcos registry changes

Conclusion

Remcos RAT is a dangerous trojan available to attackers for a relatively low 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 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
192.168.100.6
192.168.100.157
79.134.225.46
194.147.140.32
79.134.225.95
194.5.97.229
185.191.229.101
3.132.159.158
194.147.140.24
163.123.143.143
194.147.140.27
134.19.179.235
192.168.100.5
165.227.31.192
79.134.225.94
185.204.1.236
185.140.53.160
181.49.85.74
194.34.132.153
192.168.100.150
Hashes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valvesco.duckdns.org
WindowsAuthentication324-49629.portmap.host
www.secure-id6793-chase.com
frederikkempe.com
smtp.aivazibis.com
smtp.tniexpressworldwide.com
majul.com
trigonevo.com
www.allsofttech.com
nordfeet.store
343rctq4tm.joexpediagroup.com
karnnod.com
www.microvitaautism.com
jr3lllg8s.uber-asia.com
jog8o.joexpediagroup.com
d3df1srg8e.joexpediagroup.com
68b3b4b2.dns.standwithukraine.space
68b3b4b2.ns1.standwithukraine.space
squidhala.com
uqobbh9dj.joexpediagroup.com

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