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WORM_SCANDAL.A

October 08, 2012
 ALIASES:

Virus.Win32.AutoRun.abt (Kaspersky), Generic.dx (McAfee), W32.SillyFDC (Symantec), TR/Autorun.aad (Avira), Worm:Win32/Autorun.M (Microsoft)

 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

Infection Channel:

Propagates via removable drives

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.

  TECHNICAL DETAILS

File Size:

227,328 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

06 Aug 2010

Installation

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

  • %Windows%\{malware filename}.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

This worm modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = userinit.exe,kat.exe

(Note: The default value data of the said registry entry is %System%\userinit.exe,.)

Other System Modifications

This worm adds the following registry keys:

HKEY_CURRENT_USER\Software\BARRY
=

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
autorun = %Windows%\pc-off.bat

Propagation

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.

The said .INF file contains the following strings:

[autorun]
open="{malware filename}.exe %1"
shell\Open\command="{malware filename}.exe %1"
shell\Explore\command="{malware filename}.exe %1"

Dropping Routine

This worm drops the following files:

  • %Windows%\pc-off.bat

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.366.03

VSAPI PATTERN Date:

06 Aug 2010

VSAPI PATTERN Date:

8/6/2010 12:00:00 AM

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

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\Command Processor
    • autorun=%Windows%\pc-off.bat

Step 3

Delete this registry key

[ 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
    • BARRY

 

Step 4

Restore this modified 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\Windows NT\CurrentVersion\Winlogon
    • From: Userinit=userinit.exe,kat.exe
      To: %System%\userinit.exe,
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = 2
      To: 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = 1
      To: 0
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: 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. %Windows%\pc-off.bat

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_SCANDAL.A. 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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