Author: Sabrina Lei Sioting   

 

Backdoor:Win32/Qakbot.gen!B (Microsoft); Trojan.Win32.Menti.clj (Kaspersky); W32/Pinkslipbot.gen.af (NAI); Win32/Qbot.AN trojan (NOD32)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVER ALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
Low
Medium
High
Critical

  • Threat Type:
    Worm

  • Destructiveness:
    No

  • Encrypted:
    Yes

  • In the wild:
    Yes

  OVERVIEW

This worm arrives by connecting affected removable drives to a system. It arrives by accessing affected shared networks. It 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 into network drives.

  TECHNICAL DETAILS

File size: 280,576 bytes
File type: EXE
Memory resident: Yes
INITIAL SAMPLES RECEIVED DATE: 05 мая 2011

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It arrives by accessing affected shared networks.

It 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 copies of itself into the affected system:

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

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

It drops the following files:

  • %System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random foldername}\{random filename1}.dll
  • %System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random foldername}\{random filename2}.dll
  • %System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random foldername}\{random filename}.dll

(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 foldername}

(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 foldername}\{random filename}.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 foldername}\{random filename}.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 into network drives.

Other Details

This worm connects to the following possibly malicious URL:

  • {BLOCKED}34.75
  • {BLOCKED}einformation.com
  • {BLOCKED}terscentral.com
  • {BLOCKED}nelboxmanager.com
  • {BLOCKED}.co.in
  • {BLOCKED}.in
  • {BLOCKED}.in
  • {BLOCKED}.in
  • {BLOCKED}ver.com.ua
  • {BLOCKED}e.info
  • {BLOCKED}om.ua

NOTES:

Whenever a USB drive is plugged in, it randomly selects a file name in the drive and name its dropped copy as {malware file name}_{selected file name}.exe. If the drive is empty, it appends _Documents in its file name. For example, {malware_file name}_Documents.exe.

  SOLUTION

Minimum scan engine: 9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Identify and delete files detected as WORM_QAKBOT.SS using either the Startup Disk or Recovery Console

[ learnMore ]

Step 3

Delete the registry entry with an unknown data value

[ learnMore ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

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

Step 4

Restore this modified registry value

[ learnMore ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

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

Step 5

Search and delete these folders

[ learnMore ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result. %System Root%\Documents and Settings\All Users\Application Data\Microsoft\{random foldername}

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_QAKBOT.SS. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

NOTES:

For step 5, please take note of the folder location of the files detected in step 2.


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