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WORM_OTOTI.AG

October 09, 2012
 Modified by: Michael Cabel
 ALIASES:

Trojan.Win32.Generic.pak!cobra (Sunbelt)

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

  TECHNICAL DETAILS

File Size:

1,101,824 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

18 May 2012

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 and executes them:

  • %Windows%\dc.exe
  • %Windows%\SVIQ.EXE
  • %System%\WinSit.exe
  • %System%\config\Win.exe
  • %Windows%\system\Fun.exe
  • %Windows%\inf\Other.exe
  • %Windows%\Help\Other.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %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 files:

  • %Windows%\wininit.ini

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

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
dc2k5 = "%Windows%\SVIQ.EXE"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Fun = "%System%\Fun.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
dc = "%Windows%\dc.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
run = "%System%\config\Win.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe %System%\WinSit.exe"

(Note: The default value data of the said registry entry is "Explorer.exe".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%Windows%\inf\Other.exe"

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

Propagation

This worm sends copies of itself to target recipients using the following instant-messaging (IM) applications:

  • Yahoo! Messenger

It sends the following messages using the aforementioned Instant Messaging applications:

Olalala, may tinh cua ban da nhiem Worm DungCoi...........
http://{BLOCKED}ivb.googlepages.com/NWB.txt

NOTES:
This worm searches for folders and subfolders in all removable drives to drop copies of itself using the folder name as its file name.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.120.04

FIRST VSAPI PATTERN DATE:

18 May 2012

VSAPI OPR PATTERN File:

9.121.00

VSAPI OPR PATTERN Date:

19 May 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

Identify and delete files detected as WORM_OTOTI.AG using the Recovery Console

[ 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
    • dc2k5 = "%Windows%\SVIQ.EXE"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Fun = "%Windows%\system\Fun.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • dc = "%Windows%\dc.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • run = "%System%\config\Win.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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "Explorer.exe %System%\WinSit.exe"
      To: Shell = "Explorer.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • From: load = "%Windows%\inf\Other.exe"
      To: load = ""

Step 5

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. %Windows%\wininit.ini

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_OTOTI.AG. 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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