WORM_AUTORUN.ZYE

October 08, 2012
 Analysis by: Marfel Tiamzon
 PLATFORM:

Windows 98, ME, NT, 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 drops copies of itself into all the removable drives connected to an affected system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

153,594 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Jul 2009

Installation

This worm drops the following component file(s):

  • %User Temp%\z7.dll - detected as TSPY_ONLINEG.STR
  • %system%\ieso0.dll - detected as TSPY_ONLINEG.STR
  • %system%\fool0.dll - detected as TSPY_ONLINEG.STN

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It drops the following copies of itself into the affected system:

  • %system%\kxvo.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
kxva = %system%\kxvo.exe

Propagation

This worm drops copies of itself into all the removable drives connected to an affected system.

It drops the following copy(ies) of itself in all removable drives:

  • ojbss9gv.com

It 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:

{random characters}
[AutoRun]
{random characters}
open=ojbss9gv.com
{random characters}
shell\open\Command=ojbss9gv.com
{random characters}
shell\open\Default=1
{random characters}
shell\explore\Command=ojbss9gv.com
{random characters}

Dropping Routine

This worm sets the attributes of its dropped file(s) to the following:

  • Hidden
  • Read-Only
  • System

Other Details

This worm deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

8.900

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

Remove malware files dropped/downloaded by WORM_AUTORUN.ZYE

    %User Temp%\z7.dll
    %system%\ieso0.dll
    %system%\fool0.dll

Step 3

Restart in Safe Mode

[ Learn More ]

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
    • kxva=%system%\kxvo.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.ZYE. 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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