Analysis by: Sabrina Lei Sioting

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

  TECHNICAL DETAILS

File Size: 94,800 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 24 Aug 2010

Installation

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

  • %Application Data%\AdobeARMS.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 Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
AdobeARMS = %Application Data%\AdobeARMS.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Adobe Reader Speed Launchers = %Application Data%\Readers_sl.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
patches = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
AdobeARMS = \AdobeARMS.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Adobe Reader Speed Launchers = \Readers_sl.exe

Download Routine

This Trojan downloads an updated copy of itself from the following website(s):

  • http://localhostr.com/files/57a8cd/doc.exe

It saves the files it downloads using the following names:

  • %Application Data%\Readers_sl.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 then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 07.406.09
VSAPI PATTERN Date: 24 Aug 2010
VSAPI PATTERN Date: 8/24/2010 12:00:00 AM

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

Delete this registry value

[ Learn More ]

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    AdobeARMS = %Application Data%\AdobeARMS.exe
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    Adobe Reader Speed Launchers = %Application Data%\Readers_sl.exe
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    patches = 1
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    AdobeARMS = \AdobeARMS.exe
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    Adobe Reader Speed Launchers = \Readers_sl.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_BUZUS.BFQ. 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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