BKDR_QAKBOT.XE

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 opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system. It connects to a website to send and receive information.

It deletes the initially executed copy of itself.

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 file(s)/component(s):

• %Application Data%\Microsoft\Entdj\entdj32.dll - detected as TROJ_QBOTCFG.SM
• %Application Data%\Microsoft\Entdj\centdj32.dll - detected as TROJ_QBOTCFG.SM

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

• %Application Data%\Microsoft\Entdj\entdj.exe

(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 drops the following non-malicious file:

• %Application Data%\Microsoft\Entdj\entd.dll

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

• wscntfy.exe

Autostart Technique

This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\mpnhfn
Type = 10

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\mpnhfn
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\mpnhfn
ErrorControl = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\mpnhfn
DisplayName = "Remote Procedure Call (RPC) Service"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\mpnhfn
DependOnService = Dnscache

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\mpnhfn
DependOnGroup = 00

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\mpnhfn
ObjectName = "LocalSystem"

Backdoor Routine

This backdoor opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.

It connects to the following websites to send and receive information:

• {BLOCKED}istr.in
• {BLOCKED}vtkn.in.ua

Other Details

This backdoor connects to the following URL(s) to get the affected system's IP address:

• http://www.ip-adress.com/
• http://www.ipaddressworld.com/

It connects to the following possibly malicious URL:

• http://{BLOCKED}5.bluehost.com
• http://{BLOCKED}8.leavmauytdk.info/t
• http://www.{BLOCKED}edica.com/ac7.php
• http://www.{BLOCKED}y.com/
• http://www.{BLOCKED}onlyc.com/ac7.php
• http://www.{BLOCKED}agon.com/ac7.php

It deletes the initially executed copy of itself