BKDR_KIRPICH.A

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system.

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It may be dropped by the following malware:

• TROJ_ARTIEF.MA

Installation

This backdoor drops the following files:

• %Cookies%\wineck.dat - Configuration File
• %Application Data%\Microsoft\Media Player\SOUND735.WAV - Encrypted Code
• %User Profile%\a.hiv
• %User Profile%\b.hiv

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.. %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 drops and executes the following files:

• %User Profile%\Application Data\Microsoft\Messenger\Plugin\msgslang.exe - also detected BKDR_KIRPICH.A (decrypter & injector)

(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 adds the following processes:

• iexplore.exe (injected with decrypted code)

It creates the following folders:

• %User Profile%\Application Data\Microsoft\Messenger\Plugin
• %User Profile%\Application Data\Microsoft\Messenger

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

• 53ACCFO2G

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\printer

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%User Profile%\Application Data\Microsoft\Messenger\Plugin\msgslang.exe"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

• Download arbitrary files and execute it
• Get OS Version Information

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

• {BLOCKED}m.{BLOCKED}nline.us:80

As of this writing, the said servers are currently inaccessible.

NOTES:

It retrieves the timestamp of %System%\svchost.exe and modifies the timestamp of %Cookies%\wineck.dat.