1. Symantec/
  2. Security Response/
  3. W32.Yaha.U@mm


Risk Level 1: Very Low

July 1, 2003
February 13, 2007 12:03:11 PM
Also Known As:
I-Worm.Lentis.gen [KAV]
Systems Affected:

The W32.Yaha.U@mm worm:
  • Is a variant of W32.Yaha.J@mm.
  • Terminates some antivirus and firewall processes.
  • Uses its own SMTP engine to email itself to all the contacts in the Windows Address Book, MSN Messenger, .NET Messenger, Yahoo Pager, and in all the files whose extensions contain the letters HT.

The email message has a randomly chosen subject line, message, and attachment name. The attachment will have a .com, .exe, or .scr file extension.

This worm is written in the Microsoft C++ language and is compressed with ASPack.

Antivirus Protection Dates

  • Initial Rapid Release version July 1, 2003
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version July 1, 2003
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date July 2, 2003
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Writeup By: Kaoru Hayashi

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2016 Internet Security Threat Report, Volume 21
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