How to remove Backdoor:MSIL/AsyncRAT

Backdoor:MSIL/AsyncRAT – a dangerous malware attack that can result in a complete computer compromise

Backdoor:MSIL/AsyncRAT is Microsoft's detection name for a Remote Access Trojan known as AsyncRAT. This malware belongs to a category of programs that initially can be used for surveillance or educational purposes – This particular RAT is available as an open-source project for Windows. However, many malicious actors or cybercriminal groups employ these tools for nefarious purposes and inject them into companies' or users' computers, as well as networks, illegally. As a result, they serve as malware that opens a backdoor on a compromised system, allowing the attackers to perform all types of malicious actions.

Backdoor:MSIL/AsyncRAT includes an array of features that can be used for extensive monitoring practices. It can capture screenshots, view the status of anti-virus software installed on the system, log keystrokes, implement anti-analysis mechanisms to prevent detection, retrieve passwords and other sensitive data, and much more.^[1] Without a doubt, malware can result in devastating consequences, including financial losses, personal data compromise, or even identity theft.

Backdoor:MSIL/AsyncRAT virus mainly targets organizations and is used in large-scale malicious operations. The malware was previously spotted being used by several cybercriminals groups, such as TA2719,^[2] Mo Lou Qi, and others. Likewise, it was implemented within a Spamhaus botnet, which was also responsible for the delivery of other malware, including Nanocore, Agent Tesla, Remcos, Azorult, NjRat, and many others.

Despite this, since the AsyncRAT is delivered via several widespread distribution methods (for example, various cybercriminal groups might take a different approach and distribute malware via malicious spam email attachments or break in via the insecure Remote Desktop connection), home users could also be affected by it. Many already spotted Microsoft Defender flagging this infection and preventing its entrance. There were several versions of the infection observed, which include:

• Backdoor:MSIL/AsyncRAT!MTB
• Backdoor:MSIL/AsyncRAT.YA!MTB

To understand Backdoor:MSIL/AsyncRAT, it is important to understand what a backdoor is and how it correlates with its RAT functionality. As previously mentioned, Remote Access Trojans are legitimate tools that are misused by cybercriminals to monitor computers and networks illegally. They are often utilized in high-scale attacks against corporate networks for spying purposes.

A backdoor is generally a type of a Trojan that can bypass regular security measures implemented on the machine. As soon as it is installed, it allows criminals to gain administrator permissions and move laterally on the network. Thus, backdoor such as Backdoor:MSIL/AsyncRAT malware can be used to combine infected machines into a botnet that is used for delivering spam or performing DDoS attacks.

While the built-in Microsoft's security scanner can typically take care of the threat, it might also fail to eliminate all the malicious components that the Backdoor:MSIL/AsyncRAT malware brings into the PC. Besides, since a backdoor functionality allows the attackers to proliferate other malware (for example, Wacatac Trojan or Copa ransomware), it is highly recommended to scan the machine with an additional security program, such as SpyHunterCombo Cleaner or MalwarebytesMalwarebytes.

If the virus is tampering with your security software, you should access Safe Mode with Networking, as we explain below, and then download the anti-malware from there. Performing a full scan of the system should complete a full Backdoor:MSIL/AsyncRAT removal. Note that some variants of malware can sometimes disable Windows Defender as soon as it manages to reach the machine, so experts highly recommend secondary protection measures.^[3]

Finally, serious malware infections can straight out damage Windows system files, resulting in serious stability issues. In some cases, victims have to reinstall Windows in order to recover from a serious malware attack. To avoid that, we recommend using FortectIntego – this unique repair tool can fix virus damage and replace damaged Windows components with new ones.

The different approach of cybercriminal gangs: RAT distribution methods explained

As explained above, several different cybercriminal groups take on Remote Access Trojans (open source^[4] tools are especially popular) and place them on corporate networks or home computers without permission. Hence, there are many different approaches that the threat actors can take.

Here are some of the methods that can be used by cybercriminals to deliver a RAT and a backdoor onto a system:

• Another backdoor. Malware is incorporated into a complicated network and APT groups are often collaborating to maximize the profits of the illegal activities;
• Email spam or targeted emails. Phishing messages arriving in users' inboxes have been used for years, and remain one of the main attack vectors for the most prolific malware;
• Software vulnerabilities are also often chosen as the main way to deliver the malicious payload. Due to randomized nature of the attack, only those who have unpatched software installed on their systems can get infected this way;
• Repacked installers and software cracks can be placed on various websites across the web, pretending to be legitimate programs or pirated ones;
• Insecure Remote Desktop connections that are open to the internet are one of the primary choices for a corporate network break-in and exploitation.

To prevent the infection of malware, users and enterprises should ensure that adequate security measures are practiced on a regular basis. Advanced anti-malware software, regular software updates, familiarization with phishing techniques are among the primary ways of securing a computer or a network from intrusions.

Employ advanced security tools to remove Backdoor:MSIL/AsyncRAT malware

Since the AsyncRAT virus can use different distribution methods, the message of detection can be encountered at any time. To evaluate the situation better, you should always access the logs of your security software and check what exactly happened. Your anti-malware should also inform you whether it managed to remove Backdoor:MSIL/AsyncRAT successfully.

If going through the logs, you noticed that some of the components had not been deleted, it means that Backdoor:MSIL/AsyncRAT removal is not complete. In such a case, we suggest you disconnect your computer from a LAN or other network, access Safe Mode with Networking, and perform a full system scan from there. To ensure that the malware is eliminated for good, we also recommend scanning the device with a different security application.