BKDR_XTRAT.B

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 steals system information. It logs a user's keystrokes to steal information.

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.

Installation

This backdoor drops the following non-malicious files:

• %User Temp%\2.ico
• %User Temp%\barrage.doc
• %User Temp%\.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.)

It drops the following copies of itself into the affected system:

• %User Temp%\Word.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.)

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

• jhfjgj

It injects threads into the following normal process(es):

• %System%\sethc.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.)

Autostart Technique

This backdoor drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

•         .lnk

Other System Modifications

This backdoor adds the following registry entries as part of its installation routine:

HKEY_CLASSES_ROOT\hj2120431795e.dsz
(Default) = {Random HEX Values}

HKEY_CURRENT_USER\Software\jhfjgj
??????????????????????????? = OK

HKEY_CURRENT_USER\Software\jhfjgj
ServerStarted = {Date and Time of Execution}

HKEY_CURRENT_USER\Software\WinRAR SFX
C%%DOCUME~1%{User Name}%LOCALS~1%Temp = "%User Temp%"

HKEY_CURRENT_USER\Software\XtremeRAT
Mutex = jhfjgj

Backdoor Routine

This backdoor opens the following port(s) where it listens for remote commands:

• TCP port 1500

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

• {BLOCKED}g.{BLOCKED}p.org

Information Theft

This backdoor steals system information.

It logs a user's keystrokes to steal information.

Stolen Information

This backdoor saves the stolen information in the following file:

• %Application Data%\Microsoft\Windows\jhfjgj.dat

(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.)