WORM_ESFURY.SMA

 Analysis by: Sabrina Lei Sioting

 PLATFORM:

Windows 2000, XP, 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 removable drives

The dropped AUTORUN.INF is detected by Trend Micro as Mal_OtorunG.

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

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:

Varies

File Type:

EXE

Memory Resident:

Yes

Arrival Details

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

Installation

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

  • %User Profile%\{random filename}.exe

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

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
{random filename} = %User Profile%\{random filename}.exe

Other System Modifications

This worm modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

Propagation

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

  • {random filename}.exe
  • {random filename}.scr

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]
acTIOn=Open folder to view files
sheLlEXeCUTE=wOauRuD.EXE
IcON=%systEMrooT%\sYstEm32\SHELL32.DLL,4
UseAUtOPlaY=1

Other Details

This worm does the following:

  • This worm drops the following shortcut links in all removable drives connected to an affected system:
    • Documents.lnk
    • Music.lnk
    • New Folder.lnk
    • Passwords.lnk
    • Pictures.lnk
    • Video.lnk

    These shortcut links are pointed to {random filename}.exe.

NOTES:
The dropped AUTORUN.INF is detected by Trend Micro as Mal_OtorunG.

  SOLUTION

Minimum Scan Engine:

8.900

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

Remove the malware/grayware file dropped/downloaded by WORM_ESFURY.SMA

    Mal_OtorunG

Step 3

Identify and terminate files detected as WORM_ESFURY.SMA

[ Learn More ]
  1. 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.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

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
    • {random filename} = %User Profile%\{random filename}.exe

Step 5

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: ShowSuperHidden = 1

Step 6

Search and delete this file

[ Learn More ]
There may be some 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.
Documents.lnk
Music.lnk
New Folder.lnk
Passwords.lnk
Pictures.lnk
Video.lnk

Step 7

Search and delete AUTORUN.INF files created by WORM_ESFURY.SMA that contain these strings

[ Learn More ]
[AUTOruN]
acTIOn=Open folder to view files
sheLlEXeCUTE=wOauRuD.EXE
IcON=%systEMrooT%\sYstEm32\SHELL32.DLL,4
UseAUtOPlaY=1

Step 8

Scan your computer with your Trend Micro product to delete files detected as WORM_ESFURY.SMA. 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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