WORM_OTORUN.MOT

 Analysis by: Erika Bianca Mendoza

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This worm may be dropped by other malware.

It drops copies of itself into network drives.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Aug 2011

Arrival Details

This worm may be dropped by the following malware:

  • TROJ_SFXMOT.A

Installation

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

  • %Application Data%\Microsoft\IME\V2005\PHIME2002A.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It drops the following files:

  • %User Temp%\rstimgr.inf

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

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

  • 720110613
  • 820110615

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
PHIME2002A.exe = %Application Data%\Microsoft\IME\V2005\PHIME2002A.exe

Propagation

This worm drops copies of itself into network drives.

Process Termination

This worm terminates the following processes if found running in the affected system's memory:

  • wscript.exe
  • autorun.exe

NOTES:

It executes the following files bundled with this malware:

  • smcnmgr.exe - also detected by Trend Micro as WORM_OTORUN.MOT
  • winmsgr.exe - detected by Trend Micro as TROJ_SFXMOT.A

It connects to the following URLS to download and execute other files:

  • http://{base url}/bin/read_a.php?a1={some encrypted data}

where {base url} includes:

  • {BLOCKED}raze.crabdance.com
  • {BLOCKED}hecker.myftp.biz
  • {BLOCKED}ree.freebyte.us
  • {BLOCKED}apa.noads.biz
  • {BLOCKED}ara.freeoda.com
  • {BLOCKED}oro.ueuo.com
  • {BLOCKED}aba.net84.net
  • {BLOCKED}hile.00free.net
  • {BLOCKED}ara.oliwy.net
  • {BLOCKED}hop.hostmefree.org

The encrypted data in the URL contains the following information:

  • Adapter Information
  • Computer Name
  • Operating System
  • Processor Name
  • User Name

It does not continue its execution when the following process exists:

  • RsAgent.exe

It also checks if the malware runs under a virtual machine by checking the following from the obtained system information:

  • QEMU
  • VMWARE

Propagation Routine

It copies the contents of rstimgr.inf and names the file as autorun.inf in network drives. It contains the following strings:

[autorun]
icon=%SystemRoot%\system32\SHELL32.dll,8
ACTION=Windows Explorer to view files
shellexecute= autorun.exe

This automatically executes autorun.EXE when the network drive is accessed.

  SOLUTION

Minimum Scan Engine:

9.200

VSAPI OPR PATTERN File:

8.349.80

VSAPI OPR PATTERN Date:

11 Aug 2011

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

Remove malware files dropped/downloaded by WORM_OTORUN.MOT

     TROJ_SFXMOT.A

Step 3

Scan your computer with your Trend Micro product and note files detected as WORM_OTORUN.MOT

Step 4

Terminate the malware/grayware/spyware process:

[ Learn More ]
  • For Windows 98 and ME users, 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.
  • 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.
  • If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
  • Step 5

    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
      • PHIME2002A.exe = %Application Data%\Microsoft\IME\V2005\PHIME2002A.exe

    Step 6

    Search and delete this file

    [ 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. %User Temp%\rstimgr.inf

    Step 7

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

    [ Learn More ]
    WORM_OTORUN.MOT

    Step 8

    Scan your computer with your Trend Micro product to delete files detected as WORM_OTORUN.MOT. 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.

    NOTES:

    RECOMMENDATIONS:

    This malware is detected and removed by the latest Trend Micro anti-malware engine and pattern. Always keep pattern files and engines up-to-date. To know more about updating your Trend Micro product’s pattern, please refer to the following Trend Micro support page:


    Note: The steps apply for specific products indicated in the page.

    To actively detect and protect your machine, enable real-time scanning of your Trend Micro anti-malware product. Refer to the following Trend Micro support page to know more about enabling real-time scanning in your Trend Micro product:

    Enable firewall to protect against threats.


    Be aware of social engineering attacks.
    Avoid accessing the listed malicious URLs to prevent possible re-infection.
    Monitor network connections for any suspicious connection or connectivity.
    Regularly update list of sites that are trusted.
    Avoid downloading software cracks and/or pirated applications.
    Block malware related websites.
    Disconnect drives when not needed. If write access is not required, enable read-only mode only.
    Enable the scanning of Network Drive(s) in your product.


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