What is csrss.exe? Should I remove it?

Csrss.exe is a legitimate Windows process which might be exploited by criminals

Csrss.exe is an entirely safe Client Runtime Server Process by Microsoft Windows. This executable file^[1] is responsible for managing graphical instruction sets and usually located in C:\Windows\System32 directory. Note that this legitimate file should take between 4 000 – 7 000 bytes of disk space on your computer. Although, experts have recently detected Csrss.exe trojan which uses the same name as this Windows process to hide its presence on the system. 

Initially, the csrss.exe process was used for a whole graphical system, including drawing on the screen, managing windows and similar functions. With the release of Windows NT 4.0 (release date – 1996), many of these functions were moved to Windows kernel, although the process still retained responsibility of console windows and shutdown process.

Therefore, CSRSS process is an essential part of Windows, and cannot be terminated. Even if the user tries to end its task, the OS will warn that the machine will not be able to operate correctly without it, and shut down. If clicked through, windows will merely deny the shutdown of the device – it is done as a precaution to avoid system damage.

That being said, the fact that this is a standard system process, malware authors may use this name as a disguise. Any executable file should be treated as a potential threat, even if they use a legitimate name. The malicious version of the file can be used for the suspicious activity, such as: 

• personal information collection
• arbitrary files download
• digital currency mining^[2]
• infiltration of additional malware

Csrss.exe is a legitimate and essential file for Windows; therefore, executables can be replaced, duplicated or removed by malicious ones. If you noticed that more than two csrss.exe processes are running on your Windows system, you should scan your machine with anti-malware software, as it is one of the malware infection signs.

To conclude, the Client Runtime Server Process is a vital component of Windows which should run at all times. However, if you see several processes running in the task manager, you should immediately use FortectIntego or other reputable security software to remove the csrss.exe virus from your device.

Malicious programs do not ask direct permission when entering the system

Dangerous cyber threats, are created in a sophisticated way to make sure that they are able to hide their presence and avoid any suspicious activity on the computer. Likewise, criminals also name them as completely legitimate system processes to trick the users into believing that they are trustworthy. Additionally, there are other tricky distribution methods which help criminals make their infections persistent.

Therefore, it is essential to be aware that malware can be injected in the following ways:

• spam emails
• repacked or cracked software
• keygens or similar executables
• malicious websites
• weak RDP passwords
• software vulnerabilities, etc.

Therefore, always take precautions when browsing the internet, especially when it comes to spam emails, as it is the most prominent malware spreading method used by cybercriminals. Do not open attachments and, if needed, make sure that the email is legitimate before you open it.

Finally, we recommend avoiding file-sharing websites, updating software on a regular basis and scanning the machine using security software.

Get rid of Csrss.exe malware if necessary

Note that the name of Csrss.exe Windows process might be abused by hackers to hide malicious programs on the system. Although, experts from NoVirus.uk^[3] say that it is hard to determine whether the executable file is potentially dangerous or not. 

Typically, dangerous malware is capable of hiding itself well and even avoid detection by the AV engine, so it might be difficult to remove Csrss.exe malware. Best way to bypass such functionality is by entering Safe Mode with Networking and performing full system scan using FortectIntego, SpyHunter 5Combo Cleaner or Malwarebytes.

On another note, we urge users not to perform manual Csrss.exe virus removal, as it can damage the machine even further. Instead, let a profession security software do the job automatically.