Aliases: ZeroAccess (other) Zero Access (other)
Microsoft security software detects and removes this threat.
This threat is a member of the Win32/Sefnit family. This family can hide on your PC and do different things, including:
- Downloading and running other files
- Contacting remote hosts
- Disabling security features
They can also change your search results, which can generate money for malicious hackers.
Variants of Win32/Sirefef might be installed by other malware, including variants of the Trojan:Win32/Necurs family.
The following free Microsoft software detects and removes 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
Even if we've already detected and removed this particular threat, running a full scan might find other malware that is hiding on your PC.
Restore your settings
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
You can also ask for help from other PC users at the Microsoft virus and malware community.
If you’re using Windows XP, see our Windows XP end of support page.