➔
search
✕

WORM_ONLINEG.MBC

October 09, 2012
 Analysis by: Michael Cabel
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW


This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes then deletes itself afterward.

It modifies registry entries to hide files with System and Read-only attributes.

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:

102,422 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

02 Oct 2008

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

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

  • %System%2\mmvo.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It drops the following component file(s):

  • %System%2\mmvo0.dll - also detected as WORM_ONLINEG.MBC

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It executes then deletes itself afterward.

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 modifies the following registry entries to hide files with System and Read-only 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:

  • p3th8wb.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:

;{Random Characters}
[AutoRun]
;{Random Characters}
open=p3th8wb.cmd
;{Random Characters}
shell\open\Command=p3th8wb.cmd
;{Random Characters}
shell\open\Default=1
;{Random Characters}
shell\explore\Command=p3th8wb.cmd
;{Random Characters}

Download Routine

This worm downloads an updated copy of itself from the following website(s):

  • http://{BLOCKED}4g.com/rbv/uu.rar

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

5.576.04

FIRST VSAPI PATTERN DATE:

02 Oct 2008

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

Restart in Safe Mode

[ Learn More ]

Step 3

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
    • mmva = "%System%\mmvo.exe"

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = "1"

Step 5

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

[ Learn More ]


;{Random Characters}
[AutoRun]
;{Random Characters}
open=p3th8wb.cmd
;{Random Characters}
shell\open\Command=p3th8wb.cmd
;{Random Characters}
shell\open\Default=1
;{Random Characters}
shell\explore\Command=p3th8wb.cmd
;{Random Characters}

Step 6

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


Did this description help? Tell us how we did.