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F-Secure Virus Descriptions : Fagot

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



NAME:Fagot
ALIAS:IRC-Worm.Fagot, VBS.Psyme, JS/Petch.A.dropper

Summary

Fagot is an IRC worm which was found in the end of October 2003.

The spread of the worm was quickly stopped, as a web file it needed was taken offline.


A new variant of Fagot was discovered November 11th, 2003. This variant uses the link that points to home.amis.net. However, this variant of the worm is also stopped, as the file at the web site was removed.

Detailed Description

Fagot worm works by sending messages via IRC chat, trying to get people to click on a web link, which would download "britney.jpg" from www.angelfire.com.

The britney.jpg file isn't actually a picture, but a html page that contains a script code. When the page is is opened with Internet Explorer, the script is executed. The first part of the script contain Visual Basic Script code that uses an exploit to replace the Windows Media Player with a file ("patch.exe") that is downloaded from another web location. Next the second part (written with JavaScript) of the script is executed, causing the replaced medial player to execute after five seconds.

The "patch.exe" file was taken offline already by the time we got reports on this worm on Sunday the 26th of October, therefore the worm doesn't work any more.

Worm's executable component

The PATCH.EXE file is the worm's component responsible for killing anti-virus and security software tasks and for sending links to the infected HTML file to IRC networks.

The file is a Windows PE executable compressed with UPX file compressor. The packed size is 156 kilybytes, the unpacked size is about 382 kilobytes.

When the PATCH.EXE file is run, it does the following:

* Kills processes with the following names: 

 Ad-watch.exe
 regedit.exe
 taskmgr.exe

* Copies the worm's file to Windows System folder with the following name: 

 C:\Windows\system32\userinit32.exe

* Creates a startup key for the copied file in System Registry: 

 [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
 "Userinit" = "C:\Windows\system32\userinit32.exe"

* Copies the worm's file to Windows System folder with the following name: 

 C:\Windows\system32\dllhost32.exe

* Creates a startup key for the copied file in System Registry: 

 [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 "dllhost32" = "C:\Windows\system32\dllhost32.exe"

* Kills the following processes: 

 FSGK32.EXE
 FSM32.EXE
 FSMA32.EXE
 FSMB32.EXE
 FWENC.EXE
 KAVLITE40ENG.EXE
 KAVPERS40ENG.EXE
 NAV Auto-Protect
 NAVAPSVC.EXE
 NMAIN.EXE
 NORMIST.EXE
 NORTON_INTERNET_SECU_3.0_407.EXE
 NPF40_TW_98_NT_ME_2K.EXE
 NPFMESSENGER.EXE
 NPROTECT.EXE
 NPSSVC.EXE
 NSCHED32.EXE
 NTVDM.EXE
 ZAPRO.EXE
 ZAPSETUP3001.EXE
 ZATUTOR.EXE
 ZAUINST.EXE
 ZONALM2601.EXE
 ZONEALARM.EXE
 _AVP32.EXE
 _AVPCC.EXE
 _AVPM.EXE
 ccEvtMgr.exe
 ccSetMgr.exe
 FSAV32.exe
 FSMA32.exe
 FSMB32.exe
 FSSM32.exe
 AVNT.exe
 AVP.exe
 BLACKICE.exe
 FPROT.exe
 FP-WIN.exe
 N32SCANW.EXE
 NAVAPW32.EXE
 PAVCL.EXE
 PAVSCHED.EXE
 WFINDV32.EXE
 NAVW32.EXE
 BlackICE.exe

* Changes the startup page of Internet Explorer to: 

 www.blacksnake.com

* Changes default Windows logon names to: 

 COCK_SUCKING_FAGGOT

* Deletes the following files if they are present: 

 C:\windows\regedit.exe
 C:\windows\cmd.exe
 C:\windows\system32\taskman.exe
 C:\windows\system32\taskmgr.exe
 C:\windows\system32\regedt32.exe
 C:\windows\system32\regsvr32.exe
 C:\windows\TASKMAN.exe
 C:\windows\system32\autochk.exe
 C:\windows\system32\chkntfs.exe
 C:\windows\system32\chkdsk.exe
 C:\windows\system32\shutdown.exe
 C:\windows\NOTEPAD.exe
 C:\WINDOWS\system32\userinit.exe
 C:\windows\system32\progman.exe
 C:\windows\regedit.exe
 C:\windows\cmd.exe
 C:\windows\system32\taskman.exe
 C:\windows\system32\taskmgr.exe
 C:\windows\system32\regedt32.exe
 C:\windows\system32\regsvr32.exe
 C:\windows\TASKMAN.exe
 C:\windows\system32\autochk.exe
 C:\windows\system32\chkntfs.exe
 C:\windows\system32\chkdsk.exe
 C:\windows\system32\shutdown.exe
 C:\windows\NOTEPAD.exe
 C:\WINDOWS\system32\userinit.exe
 C:\windows\system32\progman.exe
 C:\windows\system32\ntoskrnl.exe
 C:\windows\system32\ntkrnlpa.exe
 C:\windows\system32\alg.exe
 C:\windows\system32\bootok.exe
 C:\windows\system32\chcp.exe
 C:\windows\system32\ctfmon.exe
 C:\windows\system32\dumprep.exe
 C:\windows\system32\recover.exe
 C:\windows\system32\imapi.exe
 C:\windows\system32\logon.exe
 C:\windows\system32\MDM.exe
 C:\windows\system32\services.exe
 C:\windows\system32\systray.exe
 C:\windows\system32\win.exe
 C:\windows\system32\wowexec.exe
 C:\windows\system32\wuauclt.exe

* Copies itself with different names: 

 C:\windows\NOTEPAD.exe
 C:\WINDOWS\system32\userinit.exe
 C:\windows\system32\progman.exe
 C:\windows\regedit.exe
 C:\windows\system32\ntoskrnl.exe
 C:\windows\system32\autochk.exe
 C:\windows\system32\chkntfs.exe
 C:\windows\system32\shutdown.exe
 C:\windows\system32\ntkrnlpa.exe
 C:\windows\system32\alg.exe
 C:\windows\system32\bootok.exe
 C:\windows\system32\chcp.exe
 C:\windows\system32\ctfmon.exe
 C:\windows\system32\dumprep.exe
 C:\windows\system32\imapi.exe
 C:\windows\system32\logon.exe
 C:\windows\system32\MDM.exe
 C:\windows\system32\recover.exe
 C:\windows\system32\services.exe
 C:\windows\system32\systray.exe
 C:\windows\system32\win.exe
 C:\windows\system32\wowexec.exe
 C:\windows\system32\wuauclt.exe

* Deletes the following Registry tree branches: 

 HKCR\
 HKLM\HARDWARE
 HKLM\SAM
 HKLM\SECURITY
 HKLM\SOFTWARE
 HKLM\SYSTEM
 HKCC\Software
 HKCC\System
 HKCU\Software\Microsoft\Internet Explorer\Desktop\SafeMode
 HKCU\Printers
 HKCU\SessionInformation
 HKLM\SYSTEM\ControlSet001\Control\SafeBoot
 HKLM\SYSTEM\\ControlSet003\\Control\\SafeBoot
 HKLM\SYSTEM\CurrentControlSet\Control\SafeBoot
 HKLM\SYSTEM\MountedDevices
 HKLM\SYSTEM\LastKnownGoodRecovery
 HKLM\SYSTEM\ControlSet001\Control\ContentIndex\Catalogs\System
 HKLM\SYSTEM\ControlSet001\Control\Biosinfo

* Shows a fake error messagebox: 

 Error


 Error in memory block: #A5487F.

* Periodically sends the following message through mIRC chat client: 

 http://www.angelfire.com/celeb2/picsx/britney.jpg <- uuh, check it out !! :D

The above changes usually severely damage Windows operating system and it has to be reinstalled.

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Detection

Detection in F-Secure Anti-Virus is in October 27th, 2003 update:

[FSAV_Database_Version]

Version=2003-10-27_01


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Write-up: Mikko Hypponen

Techical details: Katrin Tocheva, Alexey Podrezov, and Sami Rautiainen

F-Secure Corporation, October 27th - November 11th, 2003