Analysis by: Nikko Tamana
ALIASES:

Worm:Win32/Autorun!inf(Microsoft), W32/Autorun-BEK(Sophos), Win32/AutoRun.IRCBot.EM worm(Eset), W32/Autorun.JZO.worm(Panda)

 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:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware

This Trojan may be dropped by other malware.

It does not have any backdoor routine.

It does not drop any other file.

It does not have any downloading capability.

It does not have any information-stealing capability.

It automatically executes files when a user opens a drive.

  TECHNICAL DETAILS

File Size: 14,752 bytes
File Type: INF
Initial Samples Received Date: 06 Feb 2013

Arrival Details

This Trojan may be dropped by the following malware:

  • WORM_IRCBOT.LZC

Propagation

The said .INF file contains the following strings:

;{garbage}
[aUToRun]
;{garbage}
OpEN=SYSTEM.EXE
;{garbage}
ICoN=%wINdIr%\\\\sYStEM32\\\\\sHeLL32.dLL,4
;{garbage}
aCTIoN=Open folder and view files using Windows Explorer
;{garbage}
sHeLL\\\\\\oPEN=Open
;{garbage}
ShELL\\\\oPEN\\\cOMMaNd=SYSTEM.EXE
;{garbage}
uSEAUTopLaY = 1
;{garbage}
ShElL\\\\\\eXpLorE\\\CoMmAnD=SYSTEM.EXE
;{garbage}

Backdoor Routine

This Trojan does not have any backdoor routine.

Dropping Routine

This Trojan does not drop any other file.

Download Routine

This Trojan does not have any downloading capability.

Information Theft

This Trojan does not have any information-stealing capability.

Other Details

This Trojan automatically executes the following files when a user opens a drive:

  • {Removable Drive}:\SYSTEM.EXE - detected as WORM_IRCBOT.LZC

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.736.05
FIRST VSAPI PATTERN DATE: 18 Feb 2013
VSAPI OPR PATTERN File: 9.737.00
VSAPI OPR PATTERN Date: 19 Feb 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 the malware/grayware file that dropped/downloaded INF_IRCBOT.LZC

Step 3

Search and delete AUTORUN.INF files created by INF_IRCBOT.LZC that contain these strings

[ Learn More ]
  • ;{garbage}
  • [aUToRun]
  • ;{garbage}
  • OpEN=SYSTEM.EXE
  • ;{garbage}
  • ICoN=%wINdIr%\\\\\\\sYStEM32\\\\\\\\\sHeLL32.dLL,4
  • ;{garbage}
  • aCTIoN=Open folder and view files using Windows Explorer
  • ;{garbage}
  • sHeLL\\\\\\\\\\\oPEN=Open
  • ;{garbage}
  • ShELL\\\\\\\\oPEN\\\\\\cOMMaNd=SYSTEM.EXE
  • ;{garbage}
  • uSEAUTopLaY = 1
  • ;{garbage}
  • ShElL\\\\\\\\\\\eXpLorE\\\\\\CoMmAnD=SYSTEM.EXE
  • ;{garbage}

Step 4

Scan your computer with your Trend Micro product to delete files detected as INF_IRCBOT.LZC. 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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