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WORM_OTORUN.DCQ

April 11, 2011
 Analysis by: Erika 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

Infection Channel:

Propagates via flashdrives

This worm arrives by connecting affected removable drives to a system. It may be unknowingly downloaded by a user while visiting malicious websites.

It adds registry entries to enable its automatic execution at every system startup.

It drops copies of itself in all removable drives.

It connects to Internet Relay Chat (IRC) servers.

  TECHNICAL DETAILS

File Size:

93,846 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Apr 2011

Payload:

Downloads files, Connects to URLs/Ips

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This worm drops the following files:

  • %System Root%\RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\Desktop.ini

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

It drops the following copies of itself into the affected system:

  • %System Root%\RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\lin32.exe

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

It injects itself into the following processes running in the affected system's memory:

  • EXPLORER.EXE

It creates the following folders:

  • %System Root%\RESTORE
  • %System Root%\RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013

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

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{28ABC5C0-4FCB-11CF-AAX5-81CX1C635612}
StubPath = "%System Root%\RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\lin32.exe"

Propagation

This worm drops copies of itself in all removable drives.

It modifies the contents of an existing AUTORUN.INF file to automatically execute its dropped copy. It does this by adding the following strings in the .INF file:

  • [autorun]
    open=RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\lin32.exe
    icon=%SystemRoot%\system32\SHELL32.dll,4
    action=Open folder to view files
    shell\open=Open
    shell\open\command=RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\lin32.exe
    shell\open\default=1

Backdoor Routine

This worm connects to any of the following Internet Relay Chat (IRC) servers:

  • {BLOCKED].{BLOCKED}.174.5

  SOLUTION

Minimum Scan Engine:

8.900

Step 1

For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

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\Active Setup\Installed Components\{28ABC5C0-4FCB-11CF-AAX5-81CX1C635612}
    • StubPath = "%System Root%\RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\lin32.exe"

Step 3

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%\RESTORE
  • %System Root%\RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013

Step 4

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

[ Learn More ]


[autorun]
open=RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\lin32.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RESTORE\S-1-5-21-1482476501-1644491937-682003330-1013\lin32.exe
shell\open\default=1

Step 5

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