1. Symantec/
  2. Security Response/
  3. W32.Sasser.Worm


Risk Level 2: Low

April 30, 2004
February 13, 2007 12:22:21 PM
Also Known As:
W32/Sasser.worm.a [McAfee], WORM_SASSER.A [Trend], Worm.Win32.Sasser.a [Kaspersky, W32/Sasser-A [Sophos], Win32.Sasser.A [Computer Assoc, Sasser [F-Secure], W32/Sasser.A.worm [Panda]
Systems Affected:
CVE References:

W32.Sasser.Worm is a worm that attempts to exploit the vulnerability described in Microsoft Security Bulletin MS04-011. It spreads by scanning the randomly selected IP addresses for vulnerable systems.

  • Rapid Release virus definitions, version 30/04/04 rev 70 (20040430.070) and greater, detect this threat.
  • This worm has an MD5 hash value of 0xA73C16CCD0B9C4F20BC7842EDD90FC20.

W32.Sasser.Worm can run on (but not infect) Windows 95/98/Me computers. Although these operating systems cannot be infected, they can still be used to infect the vulnerable systems to which they are able to connect. In this case, the worm will waste a lot of resources so that programs cannot properly run, including our removal tool. (On Windows 95/98/Me computers, run the tool in Safe mode.)

Security Response has provided some information to aid network administrators in ongoing efforts to track down W32.Sasser.Worm infected machines on their respective network. Please see the document, "Detecting traffic due to LSASS worms" for additional information.

Antivirus Protection Dates

  • Initial Rapid Release version May 1, 2004
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version May 1, 2004
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date May 1, 2004
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Writeup By: Takayoshi Nakayama

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