arrow_back
search
close

WORM_ONLING.BA

October 09, 2012
 Analysis by: Abraham Latimer Camba
 ALIASES:

Worm:Win32/Taterf.B (Microsoft); PWS-Gamania.gen.a (McAfee); Trojan.Packed.NsAnti (Symantec); Packed.Win32.Krap.b (Kaspersky); Worm.Win32.AutoRun (fs) (Sunbelt); Packer.Malware.NSAnti.1 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

91,195 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

26 Mar 2012

Arrival Details

This worm arrives via removable drives.

It 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%\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.)

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 entries:

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

It modifies the following registry entries:

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:

  • c.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}
[AutoRun]
;{garbage}
open=c.cmd
;{garbage}
shell\open\command=c.cmd
;{garbage}
shell\open\Default=1
;{garbage}
shell\explore\Command.c.cmd
;{garbage}

Dropping Routine

This worm drops the following files:

  • %System%\drivers\{random characters}.sys
  • %System%\mmvo0.dll

(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.)

Download Routine

This worm connects to the following malicious URLs:

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

Other Details

This worm deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.866.02

FIRST VSAPI PATTERN DATE:

26 Mar 2012

VSAPI OPR PATTERN File:

8.867.00

VSAPI OPR PATTERN Date:

27 Mar 2012

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

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\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = "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.
  • %System%\drivers\{random characters}.sys
  • %System%\mmvo0.dll

Step 6

Search and delete AUTORUN.INF files created by WORM_ONLING.BA that contain these strings

[ Learn More ]
;{garbage}
 [AutoRun]
 ;{garbage}
open=c.cmd
 ; {garbage}
shell\open\command=c.cmd
 ; {garbage}
shell\open\Default=1
 ; {garbage}
shell\explore\Command.c.cmd
 ;{garbage}

Step 7

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