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TROJ_BLOCKER.A

February 08, 2014
 Analysis by: Ardin Christopher Maglalang
 ALIASES:

Win32/TrojanDownloader.VB.QJF(ESET), TR/Kazy.323825.2(ANTIVIR)

 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:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 unknowingly downloaded by a user while visiting malicious websites.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

1,078,272 bytes

File Type:

EXE

Memory Resident:

No

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 unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following copies of itself into the affected system and executes them:

  • %Application Data%\Microsoft\flashplayer.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 creates the following folders:

  • %system root%\{Random Value}

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Adobe Flash Player = "%Application Data%\Microsoft\flashplayer.exe"

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}f.biz/king.txt - contains "http://{BLOCKED}f.in/update.exe "
  • http://{BLOCKED}f.biz/ajax/icon.png
  • http://{BLOCKED}f.biz/ajax/manifest.json
  • http://{BLOCKED}f.biz/ajax/background.js
  • http://{BLOCKED}f.biz/ajax/jquery-1.9.1.min.js
  • http://{BLOCKED}f.biz/ajax/script.js
  • http://{BLOCKED}f.biz/extensions.sqlite
  • http://{BLOCKED}f.biz/firefox.xpi

It saves the files it downloads using the following names:

  • %system root%\{Random Value}\icon.png - non-malicious
  • %system root%\{Random Value}\manifest.json - non-malicious
  • %system root%\{Random Value}\background.js - contain malicious routine
  • %system root%\{Random Value}\jquery-1.9.1.min.js - non-malicious
  • %system root%\{Random Value}\script.js - non-malicious component
  • %Application Data%\Mozilla\Firefox\Profiles\4wwmjcqo.default\extensions.sqlite - non-malicious
  • %Application Data%\Microsoft\flash.xpi - malicious firefox plugins

(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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}f.in/update.exe

However, as of this writing, the said sites are inaccessible.