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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


Automatic action

Once detected, the F-Secure security product will automatically handle a harmful program or file by either deleting or renaming it.

Eliminating a Local Network Outbreak

If the infection is in a local network, please follow the instructions on this webpage:

Knowledge Base

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About the product

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Submit a sample

Submit a file or URL for further analysis.

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