Email-Worm:W32/MyDoom.AF

Classification

Category :

Malware

Type :

Email-Worm

Aliases :

MyDoom.AF, .Mydoom.ab

Summary

A new variant of MyDoom worm - Mydoom.AF, was found on October 27th, 2004. The worm is similar to previous variants.Note: Mydoom.AG was renamed to Mydoom.AF on 9th of November, 2004.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

The worm is a PE executable file 31744 bytes long packed with UPX file compressor. The unpacked file's size is 73728 bytes.

Installation to system

Upon installation the worm copies itself as 'lsasrv.exe' file to Windows System Directory and creates a startup key for that file in System Registry:

  • [HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "lsass" = "%WinSysDir%\lsasrv.exe"

where "%WinSysDir%" represents Windows System directory. If the startup key cal not be created in HKLM (local machine) Registry tree, it is created in HKCU (current user) tree.

Spreading in emails

The worm spreads by sending its infected attachment to all email addresses found on an infected computer. The worm looks for email addresses in Windows Address Book and in the files with the following extensions:

  • wab
  • pl
  • adb
  • tbb
  • dbx
  • asp
  • php
  • sht
  • vbs
  • cfg
  • eml
  • cgi
  • wsh
  • msg
  • uin
  • xls
  • jsp
  • xml
  • mdx
  • mbx
  • html
  • htm
  • txt

The worm avoids sending emails to email addresses that contain any of the following substrings:

  • avp
  • syma
  • icrosof
  • msn.
  • hotmail
  • panda
  • sopho
  • borlan
  • inpris
  • example
  • mydomai
  • nodomai
  • ruslis
  • .gov
  • gov.
  • .mil
  • foo.
  • berkeley
  • unix
  • math
  • bsd
  • mit.e
  • gnu
  • fsf.
  • ibm.com
  • kernel
  • linux
  • fido
  • usenet
  • iana
  • ietf
  • rfc-ed
  • sendmail
  • arin.
  • ripe.
  • isi.e
  • isc.o
  • acketst
  • pgp
  • tanford.e
  • utgers.ed
  • mozilla
  • root
  • info
  • samples
  • postmaster
  • webmaster
  • noone
  • nobody
  • nothing
  • anyone
  • someone
  • your
  • you
  • me
  • bugs
  • rating
  • site
  • contact
  • soft
  • no
  • somebody
  • privacy
  • service
  • help
  • not
  • submit
  • feste
  • ca
  • gold-certs
  • the.bat
  • page
  • admin
  • icrosoft
  • support
  • ntivi
  • unix
  • bsd
  • linux
  • listserv
  • certific
  • google
  • accoun

Payload

The worm modifies the HOSTS file to block access to the following websites:

  • www.symantec.com
  • securityresponse.symantec.com
  • symantec.com
  • www.sophos.com
  • sophos.com
  • www.mcafee.com
  • mcafee.com
  • liveupdate.symantecliveupdate.com
  • www.viruslist.com
  • viruslist.com
  • f-secure.com
  • www.f-secure.com
  • kaspersky.com
  • kaspersky-labs.com
  • www.avp.com
  • www.kaspersky.com
  • avp.com
  • www.networkassociates.com
  • networkassociates.com
  • www.ca.com
  • ca.com
  • mast.mcafee.com
  • my-etrust.com
  • www.my-etrust.com
  • download.mcafee.com
  • dispatch.mcafee.com
  • secure.nai.com
  • nai.com
  • www.nai.com
  • update.symantec.com
  • updates.symantec.com
  • us.mcafee.com
  • liveupdate.symantec.com
  • customer.symantec.com
  • rads.mcafee.com
  • trendmicro.com
  • www.trendmicro.com
  • www.grisoft.com
  • grisoft.com