Summary

A new variant of MyDoom worm - Mydoom.Y, was found on September 14th, 2004. It spreads in e-mails with different subject and body texts, downloads and activates a backdoor.

This variant was already detected generically as I-Worm.MyDoom.gen.

This variant seems to launch a DDoS attack against www.symantec.com.

Additional Details

The worm is a PE executable file 88640 bytes long packed with FSG file compressor. The unpacked file's size is over 118 KiB.



Installation to system

When run, the worm creates a mutex 'Sept-Symantec-Attack', copies itself as "oz11111.exe" to Windows System Directory and as "oz2.exe" in the main Windows folder. It drops several other components, registry keys are created for all the executables as follows: (First tries HKLM and falls back into HKCU if the registry key can't be openened)

[Software\Microsoft\Windows\CurrentVersion\Run] "www.symantec.com" = "%WinSysDir%\oz11111.exe"
[Software\Microsoft\Windows\CurrentVersion\Run] "Microsoft Windows updaterD" = "%WinSysDir%\log32zx.exe"
[Software\Microsoft\Windows\CurrentVersion\Run] "Services" = "%WinTempDir%\services.exe"
[Software\Microsoft\Windows\CurrentVersion\Run] "oz2" = "%WinDir%\oz2.exe"
[Software\Microsoft\Windows\CurrentVersion\Run] "Downxz" = "%WinSysDir%\Downxz.bat"


where "%WinSysDir%" represents Windows System directory, "%WinDir%" the main Windows folder and "%WinTempDir%" the Windows Temporary files folder.



The worm will also drop a text file named 'About_Mydoom.txt' in the Windows System folder, with contents refering to the actions performed by the worm, the text in the file follows:

------------------- About_Mydoom.txt contents ------------------
Contain 1- ATTACK www.symantec.com On Sept 29 2004 starting at 2 2- drops yahoo keylogger that open 4321, http://victim_ip:4321/ 3- drops 2 pictures that will not be showing to the victim 4- drops a downxz.bat which download Bacdoor.Nemog.c 5- drops services.exe , zincite.a 6- Retrieves email addresses from the Outlook address book and files on fixed disks, ram disks, and in the following registry key and folders: %Userprofile%\Local Settings\Temporary Internet Files %Userprofile%\Desktop %Userprofile%\My Documents %Userprofile%\Application Data , etc queries HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4\Wab File Name and searches for emails.
go and detect the other information.


In a difficult world In a nameless time I want to survive So, you will be mine!!,second author


Nemog and ZinCite :P¿mnopqrst
------------------- About_Mydoom.txt contents ------------------
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:

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


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

avp. syman icrosof panda sopho borlan inpris example mydomai nodomai ruslis .gov gov. .mil foo. berkeley unix math 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
The subject of infected e-mails is selected from the following variants:

Re:Help FW:Hi' Hello' Re:Test Delivery status Notification Important Re:Important FW:Important Information FW:Information Re:Information Read FW:Read Re:Read Re:Question Re:Hi Hi! News Re:News Thanks Re:Thanks FW:Thanks Re:Hello! Hello Hello! FW:Hello


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

test Please read the important document. I have attached document. Waiting for a Response. Please read the attachment. Thanks! Please see the attached file for details Please read the attached file! Please confirm! Please answer quickly! For more details see the attachment. For further details see the attachment. Monthly news report. Virus removal tool apply this patch! fun game! lol! fun! See the file. screensaverlol! See the file. Your archive is attached. check! Error !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Hello Check the attachment. Here is the attachment. :-) Here is my photo.:-) +++ Attachment: No Virus found +++ Attachment: No Infection found Norton AntiVirus - www.symantec.com F-Secure AntiVirus - www.f-secure.com Norman AntiVirus - www.norman.com Panda AntiVirus - www.pandasoftware.com Kaspersky AntiVirus - www.kaspersky.com MC-Afee AntiVirus - www.mcafee.com Bitdefender AntiVirus - www.bitdefender.com MessageLabs AntiVirus - www.messagelabs.com


The worm can send itself as an executable attachment or in a ZIP archive with one of the following names:

Virus XXX Pictures XXX Videos xbox emulator ps2 emulator Hotmail hacker yahoo hacker klez SoBig mydoom netsky Upload crack Winzip kazz Winrar mirc pyrnare SeX Vaho Fixtool Winamp
with any of the following extensions appended:

.exe .scr .pif .bat

Detection

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

[FSAV_Database_Version]
Version=2004-09-15_01



Write-up: Mikko Hypponen; September 14th, 2004;

Technical Details: Alexey Podrezov & Ero Carrera; September 15th, 2004;