WORM_IRCBOT.BZJ

 Analysis by: Cris Nowell Pantanilla

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

It receives commands from a remote malicious user via IRC. These commands are executed on the affected system. However, as of this writing, the said servers are inaccessible.

This worm arrives via removable drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It connects to Internet Relay Chat (IRC) servers.

  TECHNICAL DETAILS

File Size:

127,016 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

25 Jan 2011

Arrival Details

This worm arrives via removable drives.

Installation

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

  • {Drive:}\MSN\D\Mic.exe

It injects itself into the following processes running in the affected system's memory:

  • Explorer.exe

It creates the following folders:

  • {Drive:}\MSN
  • {Drive:}\MSN\D

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{91BPF6G1-4ELN-6M2E-BBZ9-4020406080a0}
StubPath = {Drive:}\MSN\D\Mic.exe

Propagation

This worm drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
open=MSN\D\Mic.exe
;{garbage}
action=Open folder to view files
shell\open=Open
shell\open\command=MSN\D\Mic.exe
shell\open\default=1

Backdoor Routine

This worm connects to any of the following Internet Relay Chat (IRC) servers:

  • {BLOCKED}r.{BLOCKED}ils.net
  • {BLOCKED}r.{BLOCKED}rk.biz

Other Details

This worm does the following:

  • It receives commands from a remote malicious user via IRC. These commands are executed on the affected system. However, as of this writing, the said servers are inaccessible.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.790.16

VSAPI PATTERN Date:

25 Jan 2011

VSAPI PATTERN Date:

1/25/2011 12:00:00 AM

Step 1

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\
    • {91BPF6G1-4ELN-6M2E-BBZ9-4020406080a0}

Step 3

Search and delete these folders

[ Learn More ]
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.

{Drive:}\MSN

Step 4

Search and delete AUTORUN.INF files created by WORM_IRCBOT.BZJ that contain these strings

[ Learn More ]
[autorun]
open=MSN\D\Mic.exe
;{garbage}
action=Open folder to view files
shell\open=Open
shell\open\command=MSN\D\Mic.exe
shell\open\default=1

Step 5

Search and delete these files

[ 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. {Drive:}\MSN\D\Mic.exe

Step 6

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