WORM_OTORUN.CVK

 Analysis by: Jimelle Monteser

 ALIASES:

W32/Dorkbot.AS!tr (Fortinet), Trojan-Dropper.Win32.Injector.hxsp (Kaspersky), VirTool:Win32/CeeInject.gen!A, Trojan:Win32/Ircbrute (Microsoft)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet, Propagates via removable drives, Via physical/removable drives

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 executes commands from a remote malicious user, effectively compromising the affected system.

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

118,329 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

30 Mar 2013

Payload:

Collects system information, Compromises system security, Connects to URLs/IPs, Drops files

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:

  • %Windows%\dllmgr.exe
  • %System Root%\OGa\RD\GOx.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\OGa
  • %System Root%\OGa\RD

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Bdea

It stays memory-resident by creating remote threads:

  • %Windows%\explorer.exe

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

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Dll Management Service = "dllmgr.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Installed Components\{CLSID}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Installed Components\{CLSID}
StubPath = "%System Root%\OGa\RD\GOx.exe"

Propagation

This worm creates the following folders in all removable drives:

  • {Removable Drive Letter}:\OGa
  • {Removable Drive Letter}:\OGa\RD

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=OGa\RD\GOx.exe
;ªÓÈÅÌÌüÏÐÅÎüÄÅÆÁÕÌԝ‘

;Fuck U Motha Fucka I Could have been ur Dad but the man who fucked ur mom had more change than me.
action=Open folder to view files
shell\open=Open
shell\open\command=OGa\RD\GOx.exe
shell\open\default=1

Backdoor Routine

This worm connects to any of the following IRC server(s):

  • {BLOCKED}k.{BLOCKED}nix.net

It executes the following commands from a remote malicious user:

  • Create Process
  • Propagates itself via instant messaging applications such as MSN, AIM and Triton
  • Download files/updated copy of itself
  • Join IRC channel
  • Terminates itself

As of this writing, the said servers are currently inaccessible.

Dropping Routine

This worm drops the following files:

  • %System Root%:\OGa\RD\DesKTop.ini
  • {Removable Drive Letter}:\OGa\RD\DesKTop.ini

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Information Theft

This worm retrieves the following information from the affected system:

  • OS Version
  • Host Name
  • IP address
  • Computer Name

Other Details

This worm uses the following credentials when accessing its IRC server:

  • USER NAME: rmzerm3b1tch

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.234.03

FIRST VSAPI PATTERN DATE:

23 Aug 2013

VSAPI OPR PATTERN File:

10.235.00

VSAPI OPR PATTERN Date:

24 Aug 2013

Step 1

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

Step 2

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components
    • {CLSID}

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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • Windows Dll Management Service = "dllmgr.exe"

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%:\OGa
  • {Removable Drive Letter}:\OGa

Step 6

Search and delete AUTORUN.INF files created by WORM_OTORUN.CVK that contain these strings

[ Learn More ]
[autorun]
open=OGa\RD\GOx.exe
;ªÓÈÅÌÌüÏÐÅÎüÄÅÆÁÕÌԝ‘

;Fuck U Motha Fucka I Could have been ur Dad but the man who fucked ur mom had more change than me.
action=Open folder to view files
shell\open=Open
shell\open\command=OGa\RD\GOx.exe
shell\open\default=1

Step 7

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