Analysis by: Christopher Daniel So
 Modified by: Kiyoshi Obuchi
ALIASES:

Worm:Win32/Taterf.B (Microsoft); W32.Gammima.AG (Symantec)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size: 91,034 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Aug 2008

Arrival Details

This Worm arrives via removable drives.

Installation

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

  • %System%\mmvo.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following files:

  • %System%\drivers\klif.sys

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following component file(s):

  • %System%\mmvo0.dll - detected by Trend Micro as WORM_ONLINEG.PON

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

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
mmva = "%System%\mmvo.exe"

Other System Modifications

This Worm adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\MADOWN

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoDriveTypeAutoRun = "91"

(Note: The default value data of the said registry entry is ff.)

It modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"

(Note: The default value data of the said registry entry is 1.)

Propagation

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

  • {drive letter}:\rrxf.cmd

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:

{garbage string}
[AutoRun]
{garbage string}
open=rrxf.cmd
{garbage string}
shell\open\Command=rrxf.cmd
{garbage string}
shell\open\Default=1
{garbage string}
shell\explore\Command=rrxf.cmd
{garbage string}

Other Details

This Worm attempts to access the following websites to download files, which are possibly malicious:

  • http://www.{BLOCKED}w.com/rbv/uu.rar

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 10.130.01
FIRST VSAPI PATTERN DATE: 02 Jul 2013
VSAPI OPR PATTERN File: 10.130.02
VSAPI OPR PATTERN Date: 03 Jul 2013

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Identify and terminate files detected as WORM_ONLINEG.PON

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoDriveTypeAutoRun = "91"
      To: NoDriveTypeAutoRun = "{User Preference}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = "{User Preference}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "{User Preference}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = "{User Preference}"

Step 5

Search and delete AUTORUN.INF files created by WORM_ONLINEG.PON that contain these strings

[ Learn More ]
DATA_GENERIC
  • If the lines are present, delete the file.
  • Repeat steps 3 to 6 for the remaining AUTORUN.INF files in other remaining removable drives.
  • Close Search Results.
    • *Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

    For Windows Vista, Windows 7, Windows Server 2003, Windows 8, Windows 8.1, and Windows Server 2012:

    1. Open a Windows Explorer window.
      • For Windows Vista, 7, and Server 2008 users, click Start>Computer.
      • For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
    2. In the Search Computer/This PC input box, type:
      AUTORUN.INF
    3. Select the file, then open using Notepad.
    4. Check if the following lines are present in the file:
      DATA_GENERIC
    5. If the lines are present, delete the file.
    6. Repeat steps 3 to 5 for the remaining AUTORUN.INF files in other remaining removable drives.
    7. Close Search Results.

    Step 6

    Scan your computer with your Trend Micro product to delete files detected as WORM_ONLINEG.PON. 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 the following Trend Micro Support pages for more information:


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