Analysis by: kathleenno
ALIASES:

W32.Qakbot (Symantec); Backdoor:Win32/Qakbot (Microsoft); W32/Pinkslipbot.gen.af (Mcafee); Bck/Qbot.AO (Panda)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops copies of itself in all removable drives.

  TECHNICAL DETAILS

File Size: 272,032 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 21 May 2011

Arrival Details

This worm 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 worm drops the following files:

  • %System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random characters}\{random characters}.dll - also detected as WORM_QAKBOT.BN

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

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

  • %System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random characters}\{random characters}.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random characters}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random characters} = "%System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random characters}\{random characters}.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{legitimate application} = "%System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random characters}\{random characters}.exe" /c {path and file name of legitimate application}"

(Note: The default value data of the said registry entry is {path and file name of legitimate application}.)

Propagation

This worm drops copies of itself in all removable drives.