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BKDR_POISON
Malware type: Backdoor
Destructive: No
Platform: Windows 2000, Windows XP, Windows Server 2003
Encrypted: Yes
In the wild: Yes

Overview


This description is based on a compiled analysis of several variants of BKDR_POISON. Note that specific data such as file names and registry values may vary for each variant.

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It uses legitimate program icons for its attachments to trick users into thinking they are harmless.

Technical Details


File size: Varies
Memory resident: Yes
Initial samples received date: 27 Oct 2011

Arrival Details

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Installation

This backdoor adds the following mutexes to ensure that only one of its copies runs at any one time:

  • 5-18 rat
  • 7-05'rat
  • q's rat
  • 9-15'rat
  • admin
  • 9-7'rat
  • )!VoqA.l4
  • 6as4d

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{random GUID}
StubPath = "{malware path and file name"

Propagation

This backdoor uses the following program icons for its attachments:

  • Microsoft Word
  • Flash

Backdoor Routine

This backdoor connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}rus.sytes.net
  • {BLOCKED}4.{BLOCKED}4.215.58
  • {BLOCKED}irus-groups.com
  • {BLOCKED}n.rm6.org
  • {BLOCKED}ir.no-ip.org
  • {BLOCKED}o.3322.org
  • www.{BLOCKED}4rt.org

NOTES:

It queries the default web browser by accessing the following registry entry:

HKEY_CLASSES_ROOT\http\shell\open\command

It then launches a hidden Web browser process (e.g. iexplore.exe). The malware then injects its code to the said process, which contains its backdoor routines.

This backdoor has the following capabilities:

  • Capture screen shots, webcam, audio
  • Delete, search, and upload files
  • Download and inject remote codes to legitimate processes
  • Log keystrokes and active window
  • Manage processes and services
  • Modify and search the registry entries
  • Perform a shell command
  • Send system information (IP address, computer name, user name, operating system)
  • Update/Uninstall the malware
  • View and terminate active windows and ports

Other Details

This malware may arrive contained inside a self extracting archive (RAR SFX) and attached in email messages.

The SFX drops and executes this malware as any but not limited to the following:

  • %User Temp%\anti.exe
  • %User Temp%\anti15.exe
  • %User Temp%\delete.exe
  • %User Temp%\forget.exe
  • %User Temp%\fuck.exe
  • %User Temp%\sa.exe
  • %User Temp%\so.exe
  • %User Temp%\t120k.exe
  • %User Temp%\xx.exe
  • %User Temp%\xxxx.exe

(Note:%User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

The SFX also drops any of the following encrypted component files:
  • %User Temp%\815anti.txt
  • %User Temp%\anti.txt
  • %User Temp%\hol.txt
  • %User Temp%\msvc000001a.txt
  • %User Temp%\offer.txt
  • %User Temp%\ophcrack.txt
  • %User Temp%\query.txt

(Note:%User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

Upon execution, it checks for the account user of the affected system if it has administrator rights.

If yes, it copies itself to an alternate data stream (ADS) or as physical file in the %System% directory. Their file names vary depending on the sample.

  • %System%:mstrc.scr
  • %System%:mstseca.exe
  • %System%:msvcr71.exe
  • %System%:secrm.scr
  • %System%\lsyae.exe
  • %System%\msvc81.exe
  • %System%\sysmrc.exe
  • %System%\winsys.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It the user has no administrator rights, it copies itself as any of the following:

  • %User Profile%\Application Data\mscyv.exe
  • %User Profile%\Application Data\mstrc.scr
  • %User Profile%\Application Data\secrm.scr
  • %User Profile%\Application Data\winsys.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It copies the encrypted component files as to the following:

  • %Program Files%\Common Files\ODBC\odbc.DAT
  • %Program Files%\Common Files\ODBC\ODUBC.DLL
  • %Program Files%\NetMeeting\netsa.dll
  • %Program Files%\Outlook Express\msvc7.dll
  • %System%\jql.sys
  • %Windows%\java\classes\JQB.dll
  • %Windows%\java\java.dll
  • %Windows%\system\JQB.dll
  • %Windows%\system\VER.SYS

(Note:%Program Files% is the default Program Files folder, usually C:\Program Files. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.%Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It stays memory resident by injecting codes in the following process:

  • Explorer.exe

This description is based on a compiled analysis of several variants of BKDR_POISON. Note that specific data such as file names and registry values may vary for each variant.

Solution


Minimum scan engine: 9.200

Trend customers:

    Keep your pattern and scan engine files updated. Trend Micro antivirus software can clean or remove most types of computer threats. Malware, though, such as Trojans, scripts, overwriting viruses and joke programs which are identified as uncleanable, should simply be deleted.

All Internet users:

    1. Use HouseCall - the Trend Micro online threat scanner to check for malware that may already be on your PC.
    2. Catch malware/grayware before they affect your PC or network. Secure your Web world with Trend Micro products that offer the best anti-threat and content security solutions for home users, corporate users, and ISPs. Go here for more information on Trend Micro products that fit your needs.


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Analysis By: Erika Bianca Mendoza

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