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WORM_AUTORUN.AVF

October 09, 2012
 Analysis by: Rhena Inocencio
 ALIASES:

Worm:Win32/Hamweq.A (Microsoft), W32/Autorun.worm.gen (McAfee), Packed.Generic.181 (Symantec), W32/Autorun.ALS.worm (Panda), W32/AutoRun-JA (Webroot)

 PLATFORM:

Windows 2000, XP, 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 via removable drives. It 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:

10,752 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Jul 2009

Arrival Details

This worm arrives via removable drives.

It 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 files:

  • %System Root%\RECYCLER\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%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe

(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%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe"

Propagation

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

  • {drive letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.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=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
shell\open\default=1

Other Details

This worm connects to the following possibly malicious URL:

  • {BLOCKED}7.{BLOCKED}2.146.210
  • {BLOCKED}.{BLOCKED}m.info

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

6.290.12

FIRST VSAPI PATTERN DATE:

20 Jul 2009

VSAPI OPR PATTERN File:

6.291.00

VSAPI OPR PATTERN Date:

21 Jul 2009

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 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%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe"

Step 4

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

Step 5

Search and delete AUTORUN.INF files created by WORM_AUTORUN.AVF that contain these strings

[ Learn More ]
  •  [autorun]
    open=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
    icon=%SystemRoot%\system32\SHELL32.dll,4
    action=Open folder to view files
    shell\open=Open
    shell\open\command=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.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_AUTORUN.AVF. 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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