Aliases: ZeroAccess (other) Zero Access (other)
Microsoft security software detects and removes this threat.
This family of malware uses stealth to hide its presence on your PC. Trojans in this family can do different things, including:
- Downloading and running other files
- Contacting remote hosts
- Disabling security features
Members of the family can also change search results, which can generate money for the hackers who use Sirefef.
Variants of Win32/Sirefef might be installed by other malware, including variants of the Trojan:Win32/Necurs family.
Use the following free Microsoft software to detect and remove this threat:
- Windows Defender Antivirus for Windows 10 and Windows 8.1, or Microsoft Security Essentials for Windows 7 and Windows Vista
- Microsoft Safety Scanner
- Microsoft Windows Malicious Software Removal Tool
You should also run a full scan. A full scan might find other, hidden malware.
Note that as part of the cleaning, our software might change some Windows services back to their default settings. If you had previously changed these settings, you might need to change them again.
The services that are reset include:
- BFE – Base Filtering Engine
- Iphlsvc – IP helper Service
- MSMpSvc – Microsoft Antimalware service – MSE/FEP/SCEP
- Sharedaccess – Internet Connection Sharing
- WinDefend – Microsoft Antimalware service
- Wscsvc - Windows Security Center
Get more help
If you’re using Windows XP, see our Windows XP end of support page.