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Microsoft Security Intelligence
Published Nov 09, 2004 | Updated Apr 16, 2011


Detected by Microsoft Defender Antivirus

Aliases: W32.Blaster.Worm (Symantec) W32/Lovsan.worm (McAfee) WORM_MSBLAST (Trend Micro) Win32.Poza (CA) Lovsan (F-secure) Worm.Win32.Blaster (Global Hauri) W32/Blaster (Norman) Blaster (Panda) W32/Blaster (Sophos)


The Win32/Msblast family of network worms exploit a Remote Procedure Call (RPC) Distributed Component Object Model (DCOM) vulnerability on Microsoft Windows 2000 and Windows XP systems. The worm may also attempt denial of service (DoS) attacks on some server sites, or create a backdoor program that allows attackers to access the infected system.
Recovering from recurring infections on a network
The following additional steps may need to be taken to completely remove this threat from an infected network, and to stop infections from recurring from this and other similar types of network-spreading malware:
  1. Ensure that an antivirus product is installed on ALL computers connected to the network that can access or host shares.
  2. Ensure that all available network shares are scanned with an up-to-date antivirus product.
  3. Restrict permissions as appropriate for network shares on your network. For more information on simple access control, please see:
  4. Remove any unnecessary network shares or mapped drives.
Note: Additionally it may be necessary to temporarily change the permission on network shares to read-only until the disinfection process is complete.
Removing the threat
To detect and remove this threat and other malicious software that may be installed in your computer, run a full-system scan with an up-to-date antivirus product such as the following:
For more information on antivirus software, see
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