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Virus:BDS/Codbot.AH
Date discovered:03/03/2006
Type:Worm
In the wild:No
Reported Infections:Low
Distribution Potential:Medium
Damage Potential:Medium
Static file:Yes
File size:46.080 Bytes
MD5 checksum:d209b321f972e3b4a9d9d75e40a58524
VDF version:6.31.01.34

 General Method of propagation:
   • Local network


Aliases:
   •  Symantec: W32.Toxbot
   •  Mcafee: W32/Sdbot.worm.gen.w
   •  Kaspersky: Backdoor.Win32.Codbot.ah
   •  TrendMicro: WORM_CODBOT.W
   •  VirusBuster: Worm.Codbot.Y
   •  Bitdefender: Backdoor.Codbot.AH


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


Side effects:
   • Records keystrokes
   • Registry modification
   • Makes use of software vulnerability
   • Steals information
   • Third party control

 Files It copies itself to the following location:
   • %SYSDIR%\dxdmain.exe



The following file is created:

%TEMPDIR%\erase.bat This batch file is used to delete a file.

 Registry The following registry keys are added in order to load the services after reboot:

– [HKLM\SYSTEM\CurrentControlSet\Services\dxdmain\Security]
   • "Security"=hex:%hex values%

– [HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_DXDMAIN]
   • "NextInstance"=dword:00000001

– [HKLM\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal\dxdmain]
   • @="Service"

– [HKLM\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\dxdmain]
   • @="Service"

– [HKLM\SYSTEM\CurrentControlSet\Services\dxdmain]
   • "Type"=dword:00000110
     "Start"=dword:00000002
     "ErrorControl"=dword:00000000
     "ImagePath"="%sysdir%\dxdmain.exe"
     "DisplayName"="DirectX Graphics"
     "ObjectName"="LocalSystem"
     "FailureActions"=hex:%hex values%
     "Description"="Allows you to disable DirectDraw, Direct3D, and AGP Texture Acceleration."

– [HKLM\SYSTEM\CurrentControlSet\Services\dxdmain\Enum]
   • "0"="Root\\LEGACY_DXDMAIN\\0000"
     "Count"=dword:00000001
     "NextInstance"=dword:00000001

– [HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_DXDMAIN\0000]
   • "Service"="dxdmain"
     "Legacy"=dword:00000001
     "ConfigFlags"=dword:00000000
     "Class"="LegacyDriver"
     "ClassGUID"="{8ECC055D-047F-11D1-A537-0000F8753ED1}"
     "DeviceDesc"="DirectX Graphics"

– [HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_DXDMAIN\0000\
   Control]
   • "*NewlyCreated*"=dword:00000000
     "ActiveService"="dxdmain"

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

It drops copies of itself to the following network shares:
   • ipc$
   • c$


Exploit:
It makes use of the following Exploits:
– MS02-061 (Elevation of Privilege in SQL Server Web)
– MS03-026 (Buffer Overrun in RPC Interface)
– MS04-011 (LSASS Vulnerability)
– VX05-006 (Remote Heap Overflow when using the VERITAS Backup Exec Admin Plus Pack Option)


Infection process:
Creates a TFTP or FTP script on the compromised machine in order to download the malware to the remote location.

 IRC To deliver system information and to provide remote control it connects to the following IRC Servers:

Server: **********.goingformars.com
Port: 6556
Channel: #11#
Nickname: %random character string%
Password: g3t0u7

Server: **********.my1x1.com
Port: 6556
Channel: #11#
Nickname: %random character string%
Password: g3t0u7

Server: **********.my-secure.name
Port: 6556
Channel: #11#
Nickname: %random character string%
Password: g3t0u7

Server: **********.memzero.info
Port: 6556
Channel: #11#
Nickname: %random character string%
Password: g3t0u7

Server: **********.online-software.org
Port: 6556
Channel: #11#
Nickname: %random character string%
Password: g3t0u7

Server: **********.martiansong.com
Port: 6556
Channel: #11#
Nickname: %random character string%
Password: g3t0u7



– This malware has the ability to collect and send information such as:
    • Cached passwords
    • CPU speed
    • Malware uptime
    • Information about the network
    • Size of memory
    • Information about the Windows operating system


– Furthermore it has the ability to perform actions such as:
    • Download file
    • Execute file
    • Join IRC channel
    • Kill process
    • Leave IRC channel
    • Open remote shell
    • Perform network scan
    • Start keylog
    • Start spreading routine

 Backdoor The following ports are opened:

– dxdmain.exe on a random TCP port in order to provide an FTP server.
– dxdmain.exe on UDP port 69 in order to provide a TFTP server.
– dxdmain.exe on a random TCP port in order to provide backdoor capabilities.

 Stealing It tries to steal the following information:
– Recorded passwords used by the AutoComplete function

– It uses a network sniffer that checks for the following strings:
   • OPER
   • JOIN
   • bank
   • login
   • e-bay
   • ebay
   • paypal

 Miscellaneous Mutex:
It creates the following Mutex:
   • xDxdmaiNx

 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 a runtime packer.

Description inserted by Iulia Diaconescu on Monday, March 6, 2006
Description updated by Iulia Diaconescu on Monday, March 6, 2006

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