Analysis by: Kathleen Notario
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via removable drives

This worm 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: Varies
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 21 Jul 2009
Payload: Drops files

Installation

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

  • %User Temp%\apiqq.exe
  • %User Temp%\xvassdf.exe

(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 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
54dfsger = %User Temp%\xvassdf.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
api32 = %User Temp%\apiqq.exe

Propagation

This worm drops the following copy of itself in all physical and removable drives:

  • jq.exe

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:

[AutoRun]
open=jq.exe
shell\open\Command=jq.exe

Dropping Routine

This worm drops the following files:

  • %User Temp%\4tddfwq{random number}.dll – detected as TROJ_INHOO.AE
  • %User Temp%\apiqq{random number}.dll - also detected as WORM_TATERF.DL

(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 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
VSAPI OPR PATTERN File: 6.298.02
VSAPI OPR PATTERN Date: 22 Jul 2009

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_TATERF.DL

    TROJ_INHOO.AE

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
    • 54dfsger=%User Temp%\xvassdf.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • api32=%User Temp%\apiqq.exe

Step 5

Search and delete AUTORUN.INF files created by WORM_TATERF.DL that contain these strings

[ Learn More ]
[AutoRun]
open=jq.exe
shell\open\Command=jq.exe

Step 6

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