BKDR_LIFTOH.DLF

This malware uses multi-protocol instant-messaging applications in order to propagate itself. It also has backdoor routines that steal login information from the affected system's browsers. Users with systems infected with this malware may have their online banking accounts compromised.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

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 runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.

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:

• %All Users Profile%\Application Data\{random letters}sacfsfdsf.exe

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

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

• {random string}sacfsfdsf

It injects itself into the following processes as part of its memory residency routine:

• explorer.exe

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random letters}sacfsfdsf = "%All Users Profile%\Application Data\{random letters}sacfsfdsf.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\{random letters}sacfsfdsf

It adds the following registry entries:

HKEY_CURRENT_USER\Software\{random letters}sacfsfdsf
CurrentPath111 = "%All Users Profile%\Application Data\{random letters}sacfsfdsf.exe"

Backdoor Routine

This backdoor executes the following command(s) from a remote malicious user:

• Download and execute arbitrary files
• Update itself
• Inject arbitrary routines to a running process
• Send logs
• Edit configuration

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

• http://{BLOCKED}.{BLOCKED}on.pl/p/c1.php
• http://{BLOCKED}.{BLOCKED}b.pl/p/c1.php
• http://{BLOCKED}.{BLOCKED}ws.su/p/c1.php

NOTES:

In this time of writing, this backdoor received commands from its C&C server to download from the following URLs:

• http://{BLOCKED}9.{BLOCKED}e.com/get/cb31d50f0a86e082dfafb84e78978273a5d1a258/517f8dfd/2/a293a29f1973f998/c55da70/19835y1e87i483
• http://{BLOCKED}e.com/dl/206953072/6e01dd1/19835y1e87i483.html

It saves the file it downloads using the following name:

• %All Users Profile%\Application Data\{4 random alphanumeric characters}.exe - detected as WORM_DORKBOT.SME

Its configuration consists of the following:

• C&C servers
• Connection timeout
• Number of max connection attempts
• Malware build version

The downloaded file by this backdoor can be any of the following:

• WORM_KUVAA.A
• WORM_DORKBOT.SME