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F-Secure Virus Descriptions : MyDoom.AE

[Summary] | [Detailed Description] | [Detection]



NAME:MyDoom.AE
ALIAS:I-Worm.Mydoom.AA
SIZE:51712

Summary

A new variant of MyDoom worm - Mydoom.AE, was found on October 16th, 2004. The worm is similar to previous variants. It downloads and executes an additional file from a website. This file is detected as 'Worm.P2P.Scranor'. The Scranor P2P (peer-to-peer) worm in its turn downloads and runs another file, that is detected as 'Backdoor.Win32.Rbot.gen'. The MyDoom.AE worm has a message from Mydoom author(s) to AV vendors.

Detailed Description

The worm is a PE executable file 51712 bytes long packed with UPX file compressor. The unpacked file's size is over 107 kilobytes.

Installation to system

When the worm's file is run, it first creates a mutex named 'My-Game'. Then the worm tries to download a file from the 'www.freewebs.com' website. This file is saved to the root folder of C: drive as 'Scran.exe' and is then activated. The downloaded file is a P2P (peer-to-peer) worm called 'Scranor'.

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

 [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 "Avpr" = "%WinSysDir%\avpr.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.

Also the worm creates the following key in the Registry:

 [HKLM\Software\Microsoft\Windows\DdInfect]

Spreading in e-mails

The worm spreads by sending its infected attachment to all e-mail addresses found on an infected computer. The worm looks for e-mail 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 searches for these files in the following locations:

 Desktop folder
 Temporary Internet Files folder
 My Documents folder
 Application Data folders
 Program Files folders
 Windows System folder

The files are searched on hard disks and RAM drives from C: to Z:.

The worm avoids sending e-mails to e-mail addresses that contain any of the following substrings:

 avp
 syma
 icrosof
 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

The subject of infected e-mails is selected from the following variants:

 Announcement
 Details
 Re:Details
 Information
 Re:Information
 Important
 Re:Important
 Fw:Important
 Document
 Re:Document
 Fw:Document
 Notification
 Re:Notification
 Fw:Notification
 Warning
 Re:Warning
 Fw:Warning
 read now!
 Information
 Fw:Information

The body text of infected e-mails is selected from the following variants:

 Daily Report.
 your document.
 here is the document.
 Reply
 Important Information.
 Kill the writer of this document!
 Details are in the attached document.
 See the attached file for details
 Please see the attached file for details
 Check the attached document.
 Monthly news report.
 Please confirm!.
 Please read the attached file!.
 Please see the attached file for details.
 Waiting for a Response. Please read the attachment.
 Please answer quickly!.

The worm's attachment name is selected from the following variants:

 document.doc  <spaces>  .
 report.doc  <spaces>  .
 news.doc  <spaces>  .
 msg.doc  <spaces>  .
 information.doc  <spaces>  .
 letter.doc  <spaces>  .
 message.doc  <spaces>  .
 file.doc  <spaces>  .
 check.doc  <spaces>  .
 error.doc  <spaces>  .
 archive.doc  <spaces>  .
 list.doc  <spaces>  .
 data.doc  <spaces>  .
 text.doc  <spaces>  .
 note.doc  <spaces>  .
 notes.doc  <spaces>  .
 attachment.doc  <spaces>  .

The extension of an infected file can be any of the following:

 .cpl
 .scr
 .pif

MyDoom.AE worm can also send itself in a ZIP archive.

The worm can attach a fake anti-virus scanning report to the message it sends:

 +++ Attachment: No Virus found
 <av_vendor_string>

where <av_vendor_string> string can be one of the following:

 +++ MessageLabs AntiVirus - www.messagelabs.com
 +++ Bitdefender AntiVirus - www.bitdefender.com
 +++ MC-Afee AntiVirus - www.mcafee.com
 +++ Kaspersky AntiVirus - www.kaspersky.com
 +++ Panda AntiVirus - www.pandasoftware.com
 +++ Norman AntiVirus - www.norman.com
 +++ F-Secure AntiVirus - www.f-secure.com
 +++ Norton AntiVirus - www.symantec.com

The worm fakes the sender's address. It uses the following list of names to compose the fake address:

 Leon
 Tom
 Marcus
 Troy
 Walter
 Eric
 Matthew
 Kenneth
 Charles
 Tommy
 Jim
 Francisco
 Ricky
 Dennis
 Scott
 Jason
 George
 Richard
 Lloyd
 Jay
 Leroy
 Carl
 Jerry
 Frank
 Kevin
 Donald
 David
 Bill
 Oscar
 Mario
 Henry
 Joshua
 Jeffrey
 Anthony
 Mark
 William
 Ronnie
 Miguel
 Bernard
 Douglas
 Gregory
 Larry
 Ronald
 Paul
 Michael
 Jon
 Clifford
 Alexander
 Harold
 Raymond
 Jose
 Brian
 Daniel
 Robert
 Alex
 Theodore
 Barry
 Peter
 Andrew
 Timothy
 Edward
 Thomas
 John
 Calvin
 Micheal
 Randall
 Patrick
 Stephen
 Gary
 Steven
 JosephJames

The worm uses the following list of domain names to compose the fake sender's address:

 @microsoft.com
 @symantec.com

Backdoor component

Upon installation the worm drops a file named 'TCP5424.dll' to Windows System folder. The following startup key is created in the Registry:

 [HKCR\CLSID\{E6FB5E20-DE35-11CF-9C87-00AA005127ED}\InprocServer32]
 @ = "%WinSysDir%\tcp5424.dll"

where "%WinSysDir%" represents Windows System directory. This DLL file is a backdoor that listens on TCP port 5424 for remote commands. The backdoor allows to upload and activate files on an infected computer.

Payload

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

 www.pandasoftware.com
 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
 viruslist.com
 f-secure.com
 www.f-secure.com
 kaspersky.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

Additionally the worm creates the following keys from the Registry:

 [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 "MsnMsgr"
 "ICQ Net"

The message to AV vendors

The worm contains a message to AV vendors in its body:

 Lucky's Av's ;P~. Sasser author gets IT security job and we will
 work with Mydoom , P2P worms and exploit codes .Also we will
 attack f-secure,symantec,trendmicro,mcafee , etc. The 11th of
 march is the skynet day lol . When the beagle and mydoom loose,
 we wanna stop our activity <== so Where is the Skynet now? lol.
 This Will Drop W32.Scran P2P Worm

This message is extracted by the worm to Windows System folder as 'msg15.txt' file.

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Detection

Mydoom.AE worm variant is detected as 'I-Worm.Mydoom.AA' since the following FSAV updates:

[FSAV_Database_Version]

Version=2004-10-16_01

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Write-Up: Katrin Tocheva; October 16th, 2004;

Technical Details: Alexey Podrezov; October 18th, 2004;

F-Secure Corporation