Sirefef Description

Also, known as the ZeroAccess Rootkit, Sirefef is a large family of rootkit-based PC threats that use multiple components, each cooperating with others, to target your computer with heavily-concealed and sophisticated attacks. As a configurable PC threat that includes backdoor functions, Sirefef or ZeroAccess can be used for many types of attacks, although malware researchers have found an emphasis on disabled security applications and the installation of other types of hostile software (rogue anti-virus scanners, browser hijackers and banking Trojans, for example). While removing Sirefef from your PC isn't exactly an easy task, competent and updated brands of anti-malware programs should be up to the job, especially if they're supported by common anti-malware tactics that can disable Sirefef and allow you to regain access to critical system maintenance tools. In spite of any (or no) symptoms displayed, all variants of Sirefef should be treated as high-level threats until their removal.

Why the Sirefef Family Loves Your PC's Memory a Little Too Much

PC threats from the Sirefef family have been updated for new functions on a regular basis, and malware research team notes that having anti-malware software that's just as updated may prove to be the key to being able to detect and remove a Sirefef infection. System files are often patched with Sirefef components to infect basic Windows programs. Alternately or along with this attack, many Sirefef components may be injected into a normal memory process – this makes it as good as undetectable from Task Manager, unless you happen to keep track of system resource usage for the contaminated process.

A concealed Sirefef infection can be used to hide other PC threats, damage your computer's security settings or open a backdoor exploit that allows Sirefef to enjoy unauthorized contact with criminal-controlled servers. Sirefef attacks that malware researchers consider worth explicit mentions are noted here:

  • Sirefef may disable programs that could be used to detect or remove components of a Sirefef infection. Default Windows tools (Task Manager, Windows Firewall, Windows Registry Editor, etc) are in the most danger of being disabled by these attacks, although other brands of programs are scarcely immune.
  • Sirefef may exploit your PC's resources for various forms of fraud, including generating fraudulent Bitcoin currency or simulating website 'clicks' for pay-per-click revenue models. If performed in excess, these functions can also degrade your PC's performance by noticeable levels.
  • Some file attributes may be applied without permission to arbitrary files. One common attack using this method is for Sirefef to make files appear deleted by flagging them as 'Hidden.' Most instances of this attack are accompanied by other changes that also prevent you from setting Hidden or System files to be visible.
  • Your search results may also be modified while a Sirefef infection is on your PC. This can lead to accidental exposure to malicious sites (or even just sites that are irrelevant to your searches).

Getting Wise to the Workings of a Sirefef Assault

Sirefef infections are often distributed in P2P networks as mislabeled or compromised installation packages for various types of software, especially key generators, DRM cracks and other piracy-encouraging tools. Because the dropper component of Sirefef is designed to be unobtrusive, it's unlikely that you'll be able to detect Sirefef during its installation. However, anti-malware programs can detect Sirefef-infected system drivers or, failing that, detect Sirefef when Sirefef is injected into memory (and hopefully block Sirefef at that time).

Examples of some components from the Sirefef family includeTrojan.Sirefef.Ga, Win32/Sirefef.R, Win32/Sirefef.FB.Gen, Sirefef.Y, Trojan:Win32/Sirefef.AC and Trojan:win64/Sirefef.E. malware researchers emphasize that a Sirefef infection has an extremely high chance of installing other PC threats, which makes systemic disinfection of the affected computer critical.

Use SpyHunter to Detect and Remove PC Threats

If you are concerned that malware or PC threats similar to Sirefef may have infected your computer, we recommend you start an in-depth system scan with SpyHunter. SpyHunter is an advanced malware protection and remediation application that offers subscribers a comprehensive method for protecting PCs from malware, in addition to providing one-on-one technical support service.

Download SpyHunter's Malware Scanner

Note: SpyHunter's free version is only for malware detection. If SpyHunter detects malware on your PC, you will need to purchase SpyHunter's malware tool to remove the malware threats. Learn more on SpyHunter. If you would like to uninstall SpyHunter for any reason, please follow these uninstall instructions. To learn more about our policies and practices, visit our EULA, Privacy Policy and Threat Assessment Criteria.

Why can't I open any program including SpyHunter? You may have a malware file running in memory that kills any programs that you try to launch on your PC. Tip: Download SpyHunter from a clean computer, copy it to a USB thumb drive, DVD or CD, then install it on the infected PC and run SpyHunter's malware scanner.

Technical Details

File System Modifications

Tutorials: If you wish to learn how to remove malware components manually, you can read the tutorials on how to find malware, kill unwanted processes, remove malicious DLLs and delete other harmful files. Always be sure to back up your PC before making any changes.

The following files were created in the system:

file.exe File name: file.exe
Size: 270.33 KB (270336 bytes)
MD5: 17ccd894ee2ac81292487a367ac84c53
Detection count: 57
File type: Executable File
Mime Type: unknown/exe
Group: Malware file
Last Updated: January 19, 2017
Size: 5.63 KB (5632 bytes)
MD5: 11028c6a84a967070cb1286550f2058f
Detection count: 21
File type: Dynamic link library
Mime Type: unknown/dll
Path: %WINDIR%\system32\
Group: Malware file
Last Updated: November 25, 2019
%SystemDrive%\RECYCLER\S-1-5-21-1454471165-2000478354-1801674531-1003\$82d97a3c8802be0606cf59ba8c0b2a9d\n. File name: n.
Size: 52.73 KB (52736 bytes)
MD5: ae3981ec9692fcc8861db818e761bff8
Detection count: 7
Path: %SystemDrive%\RECYCLER\S-1-5-21-1454471165-2000478354-1801674531-1003\$82d97a3c8802be0606cf59ba8c0b2a9d\
Group: Malware file
Last Updated: November 9, 2012

More files

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Posted: May 15, 2012
Threat Metric
Threat Level: 8/10
Infected PCs 138

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