Sirefef

Posted: May 15, 2012

Threat Metric

The Threat Meter is a malware assessment that SpywareRemove.com's research team is able to give every identifiable malware threat. Our Threat Meter includes several criteria based off of specific malware threats to value their severity, reach and volume. The Threat Meter is able to give you a numerical breakdown of each threat's initial Threat Level, Detection Count, Volume Count, Trend Path and Percentage Impact. The overall ranking of each threat in the Threat Meter is a basic breakdown of how all threats are ranked within our own extensive malware database. The scoring for each specific malware threat can be easily compared to other emerging threats to draw a contrast in its particular severity. The Threat Meter is a useful tool in the endeavor of seeking a solution to remove a threat or pursue additional analytical research for all types of computer users.

The following fields listed on the Threat Meter containing a specific value, are explained in detail below:

Threat Level: The threat level scale goes from 1 to 10 where 10 is the highest level of severity and 1 is the lowest level of severity. Each specific level is relative to the threat's consistent assessed behaviors collected from SpyHunter's risk assessment model.

Detection Count: The collective number of confirmed and suspected cases of a particular malware threat. The detection count is calculated from infected PCs retrieved from diagnostic and scan log reports generated by SpyHunter.

Volume Count: Similar to the detection count, the Volume Count is specifically based on the number of confirmed and suspected threats infecting systems on a daily basis. High volume counts usually represent a popular threat but may or may not have infected a large number of systems. High detection count threats could lay dormant and have a low volume count. Criteria for Volume Count is relative to a daily detection count.

Trend Path: The Trend Path, utilizing an up arrow, down arrow or equal symbol, represents the level of recent movement of a particular threat. Up arrows represent an increase, down arrows represent a decline and the equal symbol represent no change to a threat's recent movement.

% Impact (Last 7 Days): This demonstrates a 7-day period change in the frequency of a malware threat infecting PCs. The percentage impact correlates directly to the current Trend Path to determine a rise or decline in the percentage.

Threat Level:	8/10
Infected PCs:	8,886

First Seen:	September 20, 2011
Last Seen:	May 26, 2022
OS(es) Affected:	Windows

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 SpywareRemove.com 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 SpywareRemove.com 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 SpywareRemove.com 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. SpywareRemove.com 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.

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:

C:\Windows\system32\services.exe

File name: services.exe
Size: 328.7 KB (328704 bytes)
MD5: 014a9cb92514e27c0107614df764bc06
Detection count: 8,631
File type: Executable File
Mime Type: unknown/exe
Path: C:\Windows\system32\services.exe
Group: Malware file
Last Updated: June 20, 2023

c:\windows\system32\cdralw2k.dll

File name: cdralw2k.dll
Size: 5.63 KB (5632 bytes)
MD5: 11028c6a84a967070cb1286550f2058f
Detection count: 82
File type: Dynamic link library
Mime Type: unknown/dll
Path: c:\windows\system32\cdralw2k.dll
Group: Malware file
Last Updated: May 26, 2022

%SystemDrive%\RECYCLER\S-1-5-21-1123561945-329068152-1177238915-1003\$43b562c5a838baa830d22c7057894c63\n.

File name: n.
Size: 49.66 KB (49664 bytes)
MD5: b7c68d4a8c8a26616277bf1ff68d91e2
Detection count: 26
Path: %SystemDrive%\RECYCLER\S-1-5-21-1123561945-329068152-1177238915-1003\$43b562c5a838baa830d22c7057894c63
Group: Malware file
Last Updated: May 15, 2013

%SystemDrive%\RECYCLER\S-1-5-21-117609710-1292428093-842925246-1003\$6c1828419cb00d45be59384aecdadd62\n.

File name: n.
Size: 49.15 KB (49152 bytes)
MD5: ae9388af2150a021069fc330f2ba3038
Detection count: 19
Path: %SystemDrive%\RECYCLER\S-1-5-21-117609710-1292428093-842925246-1003\$6c1828419cb00d45be59384aecdadd62
Group: Malware file
Last Updated: May 15, 2013

%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