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
31 March, 2020
Global rank
11
Week rank
7
Month rank
7
IOCs
1961

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
91.193.75.126
192.169.69.25
79.134.225.35
3.137.63.131
3.20.98.123
185.244.30.123
172.94.14.24
193.161.193.99
185.140.53.154
103.147.184.15
192.64.119.164
185.244.30.69
185.244.30.125
185.140.53.4
185.244.30.124
91.170.144.1
185.244.30.32
216.38.8.168
216.38.8.180
185.244.30.20
Hashes
e4e5533a69b43f7462f19e93890ec816d15d0a6c2060ba06e1312065afc9603f
4221e9768f8998253d71077fdad8227332f7bdd09fd2cff37f9cd07efde0cf68
477b9f95d01a38672655cf452657193fbd4e82a06ca769e041ad31da49a882fa
78a7a4fd1221838620108cdc54e0c2f4beeb6003b8b6882612c87b5ebfb86646
74feb165656f8f823d446f77d8e791630359bc1f7a749964001feadb286c56b1
e997a4245d6a9b170ef2f793c3c8d778e5fe73db15aadbad8f35406daa4329e4
cc6b6c0a29a6eed79e7e915721490aac173f60a31e1096ce5aaf026d2ab2731c
4019e93f708c15eaded324f92d9a8a46756d081c8aa7ce122358ba49ab31438f
405d8e1fcde3fdc756a8c6ed4b9cedccca0cb7704e7af6a0ce83ca0fd8c6072d
18ab9aeaf57964dd36b45f260c1014ba11ef6e881a1462b62662a7e2bc9294b3
ee0f3eb8a4d7c87a4c33a1f8b08e78bb95fa7ee41ddf0b07d9b6eabe87a33b2e
a2b1384354871cbf75ed726cebcb989e0da0fe06e32949318f94e3a50ebd085b
8599ded7ef4b89944c5a5330e8608d9e1ab28acd67706284b617ddca1a7d74ab
351e1907992deaaac85fefdf4b9e58890e68e69c42a3ead259a371d25ba62cb4
41f6d12bc07b7ead9211e5746a85e896edf1aa3a8cda74602fef6cddd145c01a
f29364f4f5db7708638a70468321a13d6be5febb1ee43e441e0184a3b6c37af7
da1df4379eeef4e3d84a825ca68294bde275ca68c5cada9ed129fbf4df21daae
76f3fd920ef93c41bf7a531a32486633f09569493ea6a2a9bb45e785b9051b93
f5b31cbf4c75fd290290e437e8cb4eecca031eabbfbf823ab12f7af241bf27e6
28e8568f488b4573da6b13cd3d8601e6a624098e45d773f37e4aa6f78a4d9fc4
Domains
menorte.ddns.net
roboticsnetwork.duckdns.org
rownip.schneidstore.com
britianica.uk.com
majul.com
srvr2.callofdutyserver.pw
xeliteme.us
tats2lou.ddns.net
elx01.knas.systems
donko.duckdns.org
globaltransfersecurefilethroughcloud.duckdns.org
antipiracydetectorganisationforwsdy3film.duckdns.org
bless123.duckdns.org
notmine.duckdns.org
galli032020.duckdns.org
softnet.duckdns.org
wewewewewesesesesasbacwederffggffddsss.duckdns.org
destrors.duckdns.org
2020logs.duckdns.org
graceofgod.duckdns.org

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