Analysis by: Rhena Inocencio
ALIASES:

TrojanDownloader:JS/Qakbot.K (Microsoft), Trojan-Downloader.JS.Agent.gud (Kaspersky), JS/Downloader-FCQ (McAfee), Win32/Qbot.BD trojan (NOD32)

 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: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 6,382 bytes
File Type: JS
Initial Samples Received Date: 24 May 2013
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

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

It may be dropped by the following malware:

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}istr.in/4
  • http://{BLOCKED}vtkn.in.ua/4
  • http://{BLOCKED}uytdk.info/4
  • http://{BLOCKED}asudskfoe.org/4
  • http://{BLOCKED}iakfuuasd.net/4
  • http://{BLOCKED}s.{BLOCKED}v.ua/4
  • http://{BLOCKED}m.{BLOCKED}v.ua/4
  • http://{BLOCKED}n.org/4
  • http://{BLOCKED}nz.net/4
  • http://{BLOCKED}mausj.org/4
  • http://{BLOCKED}tkrich.net/4
  • http://{BLOCKED}carusled.org/4

It saves the files it downloads using the following names:

  • %Temp%\~{script name}.exe

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.938.07
FIRST VSAPI PATTERN DATE: 24 May 2013
VSAPI OPR PATTERN File: 9.939.00
VSAPI OPR PATTERN Date: 24 May 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Remove malware/grayware files that dropped/downloaded JS_QBOT.BCJ

    • BKDR_QAKBOT
    • WORM_QAKBOT

Step 3

Search and delete this file

[ Learn More ]

There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.  
  • %Temp%\~{script name}.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_QBOT.BCJ. 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.


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