Java:Malware-gen [Trj] Trojan – How to Detect and Remove CrossRAT

Java:Malware-gen [Trj] Trojan – How to Detect and Remove CrossRAT

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This article has been created in order to explain what is the CrossRAT Trojan Horse infection and how to remove it completely from your computer.

A new, highly dangerous Trojan horse going by the detection Trojan:Java/Trupto has been reported to cause immense harm to Linux, Windows and MacOS computer. The Trojan is a RAT (Remote Access Trojan) type and is dubbed CrossRAT by researchers. The virus is written in JavaScript and it can perform series of dangerous activities on computers once it infects them, ranging from modifying files, writing files, taking screenshots and running DLLs to infect your computer with other viruses. The CrossRAT Trojan has been reported by series of researchers to come onto victim computers via a .jar file via series of methods with very low detection rate. Read this article to learn more about the CrossRAT Trojan plus methods on how to remove it from your computer plus how to secure it against further infections.

Threat Summary

TypeRemote Access Trojan
Short DescriptionAims to infect the computer and remain silently on the victim’s computer in order to allow hackers to control it from distance.
SymptomsThe CrossRAT Trojan is generally designed to remain silent, but new files may be created on your PC plus infected computers may act strangely.
Distribution MethodVia malicious web links, infected e-mail attachments as well as fake setup files and programs.
Detection Tool See If Your System Has Been Affected by CrossRAT


Malware Removal Tool

User ExperienceJoin Our Forum to Discuss CrossRAT.

CrossRAT Trojan – How Does It Infect

The CrossRAT Trojan may enter your computer via many different methods, the main suspect of which is via a malicious web redirect to a page which automatically downloads and runs the .jar files which causes the infection. One sample of the malicious file, infecting with the CrossRAT Trojan has been reported to have the following technical parameters according to VirusTotal:

→ SHA-256 15af5bbf3c8d5e5db41fd7c3d722e8b247b40f2da747d5c334f7fd80b715a649
Name: hmar6.jar
Size:217.33 KB

The bad news here is that no system is secure, even Linux OS. This suggests that very experienced malware writers may be behind this remote access Trojan.

The main method by which you may have come into contact with the CrossRAT trojan is if you have visited a web page, which causes an automatic browser redirect to a web page which can infect you simply by you having to visit it.

Another way by which you may become a victim of this Trojan horse is if you have opened a file, which you believe is legitimate and it contains the CrossRAT infection script which causes the infection by you opening the file. Such files are often fake setups of programs, fake key generators, game cracks and other software you may have downloaded via Torrent websites.

The last but not least important method by which this Trojan may have infected your computer is if you have opened an e-mail attachment, like an infected Microsoft Office document, believing it is a legitimate invoice, receipt for purchase online or other form of seemingly legitimate file. Such e-mails often pretend to come from companies from the likes of eBay, PayPal, DHL and other reputable names.

CrossRAT Trojan – Analysis

Remote access Trojans are not a new concept. However, when we see a RAT which is compatible with the three most widely used operating systems in the world – Windows, MacOS and Linux, it is definitely a cause for alarm. Furthermore, the EFF have established that the Trojan has been created and supported by the Dark Caracal hacker group, which may be based on Lebanon in order to spy on government employees and journalists in more than 20 countries all over the globe.

The CrossRAT Trojan has many capabilities, the primary of which are:

  • To evade conventional anti-virus software protection.
  • To manipulate the files on the computers it infects.
  • To run DDL files which may contain other viruses, like miner malware or ransomware.

According to a technical report by ex-NSA hacker Partrick Wardle, the activity of the malware once it infects your computer is very sophisticated and experienced developers are behind it. Once this Trojan finds itself in a computer system, it perform the following steps:

1-Scans the infected computer in order to establish the OS it’s running, the security software installed on it.
2-Uses the information from scanning the infected PC in order to infect it with the tools which are most likely to be undetectable.
3-Assumes administrative access to gain full control of the infected machine.

The CrossRAT Trojan can be identified on different computers based on different modifications it performs on different OS’s. Here are it’s main symptoms that give it away:

For Windows PC’s:

HKCU\Software\Microsoft\Windows\CurrentVersion\Run\ in which a value string is added, containing Data in which the “java”, “-jar” and “mediamgrs.jar” commands are present.

For MacOS computers:

Mediamgrs.jar, dropped in ~/Library and a launch agent is dropped in ~/Library/LaunchAgens, called mediamgrs.plist

For Linux computers:

The .jar file mediamgrs.jar is created in the /usr/var directory plus an “autostart” type of file is added in ~/.config/autostart/ which may be named mediamgrs.desktop

It is advisable to immediately take action in case you see any hints of having CrossRAT on your computer and if you see any of the detections we have described in the “Detect and Remove” section below to perform the following activities as described methodically:

1. Stop your Internet Access.
2. Change all of your passwords on your online accounts from a secure PC.
3. Move all of your important files on a flash drive from your PC or use other method to transfer them.
4. After having done those, follow the instructions from the “Detect and Remove” paragraph below.

CrossRAT Trojan – How to Detect and Remove

CrossRAT Trojan is detected by most antivirus engines under the following names:

CrossRAT Detection names

In order to remove this virus, you should follow the manual or automatic removal instructions down below. They are specifically designed in order to help you to delete this virus methodologically. Be advised that if you feel unsure to delete the CrossRAT Trojan manually, experts strongly advise to do so automatically by downloading an advanced anti-malware tool as it is likely the best option to fully erase this malware and secure your computer at a click of a button.


Ventsislav Krastev

Ventsislav has been covering the latest malware, software and newest tech developments at SensorsTechForum for 3 years now. He started out as a network administrator. Having graduated Marketing as well, Ventsislav also has passion for discovery of new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management and then Network Administration, he found his passion within cybersecrurity and is a strong believer in basic education of every user towards online safety.

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