BKDR_QAKBOT.RV

April 15, 2013
 Analysis by: Rhena Inocencio
 ALIASES:

Backdoor:Win32/Qakbot.gen!C (Microsoft), Trojan.Win32.Pincav.cmxz (Kaspersky), W32.Qakbot (Symantec), W32/Pinkslipbot!96EBCC17F97F (Nod32), Backdoor.Win32.Qakbot (Sunbelt)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 is injected into all running processes to remain memory resident.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

258,048 bytes

File Type:

EXE

Initial Samples Received Date:

11 Apr 2013

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:

  • %Application Data%\Microsoft\{random folder name}\{random file name}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It is injected into all running processes to remain memory resident.

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 name} = "%Application Data%\Microsoft\{random folder name}\{random file name}.exe"

It modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ctfmon.exe = ""%Application Data%\Microsoft\{random folder name}\{random file name}.exe" /c %System%\ctfmon.exe"

(Note: The default value data of the said registry entry is %System%\ctfmon.exe.)

Other Details

This backdoor drops the following file(s)/component(s):

  • %Application Data%\Microsoft\{random folder name}\{random file name 2}.dll

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It deletes the initially executed copy of itself