Worm/Autorun.bft - Worm

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Summary

Full description

Statistics

Virus:	Worm/Autorun.bft
Date discovered:	11/09/2008
Type:	Worm
In the wild:	Yes
Reported Infections:	Low
Distribution Potential:	Low to medium
Damage Potential:	Low to medium
Static file:	Yes
File size:	453.394 Bytes
MD5 checksum:	ab1bf0316b7fd768c11958001d37b640
IVDF version:	7.00.06.148 - Thu, 11 Sep 2008 17:09 (GMT+1)

General Method of propagation:
   • Local network

Aliases:
   • Symantec: W32.Imaut
   • Kaspersky: Trojan.Win32.Autoit.dt
   • F-Secure: Trojan.Win32.Autoit.dt

Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003

Side effects:
   • Downloads files
   • Drops files
   • Registry modification

Files It copies itself to the following locations:
   • %SYSDIR%\csrcs.exe
   • %network shares%\%random character string%.exe

It deletes the initially executed copy of itself.

The following files are created:

– Temporary files that might be deleted afterwards:
   • %TEMPDIR%\aut1.tmp
   • %TEMPDIR%\aut2.tmp
   • %TEMPDIR%\%random character string%
   • %TEMPDIR%\%random character string%

– %SYSDIR%\autorun.inf This is a non malicious text file with the following content:
   • %code that runs malware%

– %TEMPDIR%\suicide.bat Furthermore it gets executed after it was fully created. This batch file is used to delete a file.

It tries to download some files:

– The location is the following:
   • http://www.whatismyip.com/**********/n09230945.asp
It is saved on the local hard drive under: %temporary internet files%\Content.IE5\%random character string%\n09230945[1].htm

– The location is the following:
   • http://sousi.extasix.com/**********.htm
It is saved on the local hard drive under: %temporary internet files%\Content.IE5\%random character string%\genst[1].htm

Registry The following registry key is added in order to run the process after reboot:

– [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
   • "Shell"="Explorer.exe csrcs.exe"

The following registry key is added:

– [HKLM\SOFTWARE\Microsoft\DRM\amty]
   • "ilop"="1"
   • "fix"=""
   • "exp1"="%hex values%"
   • "dreg"="%hex values%"
   • "eggol"="0"
   • "regexp"="%number%"

The following registry keys are changed:

Various Explorer settings:
– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\
   Run]
   New value:
   • "csrcs"="c:\windows\\system32\\csrcs.exe"

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
   New value:
   • "Hidden"=dword:00000002
     "SuperHidden"=dword:00000000
     "ShowSuperHidden"=dword:00000000

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\
   Folder\Hidden\SHOWALL]
   New value:
   • "CheckedValue"=dword:00000001

Network Infection In order to ensure its propagation the malware attemps to connect to other machines as described below.

It drops a copy of itself to the following network share:
• %network shares%\%random character string%.exe

File details Programming language:
The malware program was written in MS Visual C++.

Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with the following runtime packer:
• UPX

See a brief description here.

Description inserted by Andreas Feuerstein on Thu, 11 Sep 2008 13:01 (GMT+1)
Description updated by Andreas Feuerstein on Tue, 16 Sep 2008 10:00 (GMT+1)

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