Analysis by: JasperM
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm may be downloaded by other malware/grayware from remote sites. It may be dropped by other malware.

It receives commands from a server that may be controlled by a bot or a malicious user.

  TECHNICAL DETAILS

File Size: 20,992 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 04 Aug 2010
Payload: Connects to URLs/Ips, Drops files

Arrival Details

This worm may be downloaded by the following malware/grayware from remote sites:

  • WORM_BUZUS.SMX

It may be dropped by other malware.

It may be downloaded from the following remote sites:

  • http://{BLOCKED}.{BLOCKED}.92.250/pr.exe

Installation

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

  • %System Root%\RECYCLER\S-1-5-21-0243936033-3052116371-381863308-1811\vsbntlo.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%\RECYCLER
  • %System Root%\RECYCLER\S-1-5-21-0243936033-3052116371-381863308-1811

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

It injects threads into the following normal process(es):

  • EXPLORER.EXE

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
12CFG214-K641-12SF-N85P = %System Root%\RECYCLER\S-1-5-21-0243936033-3052116371-381863308-1811\vsbntlo.exe

Backdoor Routine

This worm connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}3.hmarhelo.com

Denial of Service

This worm receives commands from a server that may be controlled by a bot or a malicious user.

  SOLUTION

Minimum Scan Engine: 8.9
VSAPI OPR PATTERN File: 7.390.07
VSAPI OPR PATTERN Date: 17 Aug 2010

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

Restart in Safe Mode

[ Learn More ]

Step 3

Remove malware files dropped/downloaded by WORM_BUZUS.ARR

    •  WORM_BUZUS.SMX

Step 4

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
    • 12CFG214-K641-12SF-N85P=%System Root%\RECYCLER\S-1-5-21-0243936033-3052116371-381863308-1811\vsbntlo.exe

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_BUZUS.ARR. 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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