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BKDR_QAKBOT.PR

March 01, 2013
 Analysis by: Rhena Inocencio
 ALIASES:

Backdoor:Win32/Qakbot (Microsoft), W32.Qakbot (Symantec), W32/Pinkslipbot.gen.bm (McAfee), Win32/Qbot.BB trojan (ESET), 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 deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

262,144 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

27 Feb 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}i.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.)

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}i.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}i.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}.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