WORM_OTORUN.GY

October 09, 2012
 Modified by: Sabrina Lei Sioting
 ALIASES:

Trojan.Win32.Generic!BT (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

Infection Channel:

Propagates via removable drives

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.

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

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

131,073 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Jun 2012

Payload:

Drops files

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:

  • %System Root%\DRIVE\BIN\April2.exe

(Note: %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%\DRIVE
  • %System Root%\DRIVE\BIN

(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\{67KLN5J0-4OPM-33WE-AAX5-21KC2A1112233}
StubPath = "%System Root%\DRIVE\BIN\April2.exe"

Other System Modifications

This worm adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{67KLN5J0-4OPM-33WE-AAX5-21KC2A1112233}

Propagation

This worm creates the following folders in all removable drives:

  • DRIVE
  • DRIVE\BIN

It drops the following copy(ies) of itself in all removable drives:

  • DRIVE\BIN\April2.exe

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=DRIVE\BIN\April2.exe
;
;½½¾¡´¿²¾¼¼°¿µì
;
;
;ah ya salam saalam salaaam ya salaaam bla bla bla lolguy made somthing seems cool.
action=Open folder to view files
shell\open=Open
shell\open\command=DRIVE\BIN\April2.exe
shell\open\default=1

Dropping Routine

This worm drops the following files:

  • %System Root%\DRIVE\BIN\Desktop.ini

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

Other Details

This worm connects to the following possibly malicious URL:

  • {BLOCKED}.botsgod.info
  • {BLOCKED}.whisper.im
  • {BLOCKED}.psybnc.cz

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.200

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 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
    • {67KLN5J0-4OPM-33WE-AAX5-21KC2A1112233}

Step 4

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%\DRIVE
  • {removable drive}\DRIVE
    •  

Step 5

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

[ Learn More ]
[autorun]
open=DRIVE\BIN\April2.exe
;
;½½¾¡´¿²¾¼¼°¿µì
;
;
;ah ya salam saalam salaaam ya salaaam bla bla bla lolguy made somthing seems cool.
action=Open folder to view files
shell\open=Open
shell\open\command=DRIVE\BIN\April2.exe
shell\open\default=1

Step 6

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