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


Risk Level 2: Low

May 9, 2004
February 13, 2007 12:22:50 PM
Systems Affected:
CVE References:

W32.Sasser.E.Worm is a minor variant of W32.Sasser.Worm. It attempts to exploit the LSASS vulnerability, described in Microsoft Security Bulletin MS04-011, and spreads by scanning randomly selected IP addresses for vulnerable systems.

W32.Sasser.E.Worm differs from W32.Sasser.Worm as follows:
  • Uses a different mutex: SkynetNotice.
  • Uses a different file name: lsasss.exe.
  • Creates a different value in the registry: "lsasss.exe"
  • Uses different port numbers, used by FTP server and the remote shell: 1023 and 1022.
  • After 2 hours of running it displays a message.
  • It deletes the values from the registry, which are known to be installed by Trojan.Mitglieder, W32.Beagle.W@mm, and W32.Beagle.X@mm.
  • The name of the file retrieved from the FTP server is followed by _update.exe.
  • The worm logs data into the file C:\ftplog.txt.
  • Has an updated routine for finding vulnerable computers. W32.Sasser.E.Worm sends an ICMP echo request before attempting to make a connection. This change may prevent the worm from properly executing on Windows 2000 systems.

W32.Sasser.E.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 vulnerable computers.

Antivirus Protection Dates

  • Initial Rapid Release version May 9, 2004
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version May 9, 2004
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date May 9, 2004
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Writeup By: Sergei Shevchenko

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