BKDR_XTRAT.JT

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.

However, as of this writing, the said sites are inaccessible.

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 copies of itself into the affected system and executes them:

• %User Temp%\ie4uinit.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 file(s)/component(s):

• %Application Data%\Microsoft\Crypto\RSA\S-1-5-21-1614895754-436374069-682003330-1003\c0528c2346cb928a9052304ef3ab8fd4_411f3a52-26ed-4872-9a07-8c966acba234

(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.)

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ie4uinit.exe = %User Temp%\ie4uinit.exe -h"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\XtremeRAT
Mutex = "--((Mutex))--"

HKEY_CURRENT_USER\Software\--((Mutex))--
ServerStarted = "{Date and Time}"

It adds the following registry keys as part of its installation routine:

HKEY_CLASSES_ROOT\rr1081767346z.ypa

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
rr1081767346z.ypa

Backdoor Routine

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

• TCP port 8888

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

• http://{BLOCKED}g.{BLOCKED}p.org:1500/1411.functions

However, as of this writing, the said sites are inaccessible.

Information Theft

This backdoor steals system information.

It logs a user's keystrokes to steal information.

Stolen Information

The stolen information is saved in the following file:

• %Application Data%\Microsoft\Windows\--((Mutex))--.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.)