WORM_OTORUN.HIS

May 17, 2013
 Analysis by: Rika Joi Gregorio
 ALIASES:

VirTool:Win32/CeeInject.gen!DG(Microsoft), W32/AutoRun-BNV(Sophos), W32/Injector.CCW!tr(Fortinet), W32/Palevo.HT (exact)(FProt), Win32/Bflient.K worm(Eset)

 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:

  • 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.

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

  TECHNICAL DETAILS

File Size:

92,160 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

09 May 2013

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:

  • %Application Data%\onst.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = "%Application Data%\onst.exe"

Propagation

This worm creates the following folders in all removable drives:

  • {Drive Letter}:\open

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

  • {Drive Letter}:\open\client.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:

;{garbage codes}
[autorun
;{garbage codes}
open=open/client.exe
;{garbage codes}
icon=%SystemRoot%\system32\SHELL32.dll,4
;{garbage codes}
action=Open Folder to view files using Windows Explorer
;{garbage codes}
sHell\\open\command=open/client.exe
;{garbage codes}
sHell\open\\command=open/client.exe
;{garbage codes}
useautoplay=1
;{garbage codes}

Other Details

This worm connects to the following possibly malicious URL:

  • http://{BLOCKED}l.{BLOCKED}2po3.info
  • http://{BLOCKED}l.{BLOCKED}e.info
  • http://{BLOCKED}l.{BLOCKED}x.eu

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.922.05

FIRST VSAPI PATTERN DATE:

16 May 2013

VSAPI OPR PATTERN File:

9.923.00

VSAPI OPR PATTERN Date:

16 May 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 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
    • Taskman = "%Application Data%\onst.exe"

Step 4

Search and delete this folder

[ 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. DATA_GENERIC
  • In the Look In drop-down list, select My Computer, then press Enter.
  • Once located, select the folder then press SHIFT+DELETE to permanently delete the folder.

    • Step 5

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

    [ Learn More ]
    ;{garbage codes}
    [autorun
    ;{garbage codes}
    open=open/client.exe
    ;{garbage codes}
    icon=%SystemRoot%\system32\SHELL32.dll,4
    ;{garbage codes}
    action=Open Folder to view files using Windows Explorer
    ;{garbage codes}
    sHell\\open\command=open/client.exe
    ;{garbage codes}
    sHell\open\\command=open/client.exe
    ;{garbage codes}
    useautoplay=1
    ;{garbage codes}

    Step 6

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