How to remove Sality virus

Sality – is a self-propagating worm that was first introduced back in 2003 but is still prevalent today

Sality virus is a complex and multi-functional malware family that was first spotted in the wild back in 2003. Capable of spreading via infected removable drives and network shares, the worm operates by infecting all the .exe and .scr files on the host system – it is a typical functionality of a virus.

Security researchers believe that the Sality virus originated in Russia and evolved significantly over the years. Since 2010, the malware employed rootkit^[1] capabilities, as well as used peer-to-peer network (botnet) to communicate with the infected computers. While different versions exhibit different symptoms and perform particular functions on the infected computer, most Sality variants are worms^[2] that are capable of replicating themselves by using autorun^[3] functionality.

Sality virus family is relatively old, but by no means, it is no longer a threat. It can use sophisticated evasion techniques like feeding its .dll files directly into memory and naming the main executables by using randomly generated names, which consequently prevents AV detection. Besides being able to send out spam, record keystrokes, steal sensitive information, etc., Sality is also continually communicating with its remote server to receive necessary updates and improve its functionality by implementing new modules (such as Trojan downloader, for example).

For the infection process, Sality virus drops two different .dll files (wmdrtc32.dll and wmdrtc32.dl_) into %SYSTEM% folder, which are later executed. However, more advanced variants of the worm do not drop any DLLs into the system but instead use the memory, meaning, no files are written on the disk. During the infection process, Sality may create a random driver file and place it into the %SYSTEM%\drivers folder.

Sality virus executes several sets of commands that infect all the EXE and SCR files located on the Windows computer. The worm then quickly spreads to all the virtual and physical devices connected to the same network. It also modifies the original host code at the entry point to reroute the execution to the polymorphic^[4] viral code – it runs mutated algorithms to perform the same tasks each time the computer is booted. Additionally, Sality worm makes several changes in Windows Registry to be able to start with every Windows boot. The affected keys include (nevertheless, there are also several other keys that the virus creates, modifies, and deletes):

HKEY_CURRENT_USER\Software\Microsoft\Windows\ShellNoRoam
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

Sality virus works as a malware downloader, which uses a preset list of URLs that point to the source where additional files can be downloaded, decrypted, and then executed. The cyber threat uses an RC4 encryption algorithm to encrypt and decrypt data used in the host infection process.

After infecting the machine, Sality virus uses lists of predetermined URLs to establish multiple HTTP connections, which consequently feeds the payload with the newest updates and can also inject new modules into the affected computer.

To be able to remove Sality virus, it is important not to ignore signs of the infection, which include:

• The installed security software starts malfunctioning or is terminated;
• Security-related services and processes are stopped;
• Booting into Safe Mode becomes impossible;
• The malware starts sending malicious emails;
• The presence of a  malicious file amsint32.sys located in %SystemRoot%\system32\drivers

Sality virus removal can be a complicated task because it can name its own executable by any name. Therefore, AV engines that use a preset list of malware names to detect it might fail to do so. Nevertheless, please check the last part of the article for full eradication instructions, and then you can clean all the malware traces using FortectIntego.

Computer infections via contaminated external drives and networks are still a huge risk

Users typically infect their computers with malicious software due to a lack of security measures. Some users are not aware of certain things that need to be done in order to protect themselves, while others simply neglect adequate security means and end up infecting their computers with dangerous malware.

One of the most important rules is to obtain reputable security software. While the Sality virus is old, security software developers implemented appropriate preventive measures to keep the malware away. However, you need to make sure that AV's database is continuously updated. Additionally, patching all the programs installed on the computer is vital as well. Software vulnerabilities are often used to infect malware automatically (that includes the operating system as well).

Finally, you should be aware that some files that look normal might be actually malicious. Therefore, you should never insert USB flash drives, SSD, or other external drives if you are not sure that they are safe to use. Unfortunately, you cannot be sure about that 100%, so you should let reputable anti-malware software to block such content before it manages to spread. Also, as a general rule, you should never open unknown files you download from the internet before you check them with tools like Virus Total (this includes pirated software, which is not recommended to download in the first place).

Sality virus removal steps

Sality virus removal is a complicated task, that is why preventing it is critical. Nevertheless, if you suspect that your computer is infected with this malware, you should perform several tasks to make sure that the cyber threat is gone. 

There are different types of Sality viruses around. Therefore, in some cases, scanning your machine with robust security software will do the trick. Unfortunately, as we mentioned above, the malware typically stops the operation of multiple AV providers, and booting the system in Safe Mode might be impossible as well.

Some anti-virus vendors created tools that are specifically designed to remove Sality virus. AVG provides a Sality fix, and you can also make use of Kaspersky's Salitykiller. Once the malware is gone, you should make use of FortectIntego or SpyHunterCombo Cleaner to fix all the damage done to the machine – remember, the worm infects system files and anti-malware software typically can not repair the corrupted files. Therefore, use applications that can remediate your PC and restore Registry files.

Finally, security experts^[5] do not recommend removing Sality manually, as the infection changes various parameters on the system. Thus, finding it and reverting the changes is an extremely complicated task that should only be practiced by trained IT specialists.