Worm:Win32/Conficker.B is a worm that infects other computers across a network by exploiting a vulnerability in the Windows Server service (SVCHOST.EXE). If the vulnerability is successfully exploited, it could allow remote code execution when file sharing is enabled. It may also spread via removable drives and weak administrator passwords. It disables several important system services and security products.


The following system changes may indicate the presence of this malware:

  • The following services are disabled or fail to run:
    • Windows Update Service
    • Background Intelligent Transfer Service
    • Windows Defender
    • Windows Error Reporting Services
  • Some accounts may be locked out due to the following registry modification, which may flood the network with connections:
  • Users may not be able to connect to websites

Also Known As

  • TA08-297A (other)
  • CVE-2008-4250 (other)
  • VU827267 (other)
  • Win32/Conficker.A (CA)
  • Mal/Conficker-A (Sophos)
  • Trojan.Win32.Agent.bccs (Kaspersky)
  • W32.Downadup.B (Symantec)
  • Confickr (other)
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