WORM_AUTORUN.CXE

 Analysis by: Michael Jay Villanueva

 ALIASES:

Worm:Win32/Hamweq.A (Microsoft); Worm.AutoRun (Malwarebytes); WORM/Autorun.phg (Avira)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • 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:

118,784 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

06 Jan 2012

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%\RESTORE\{Random}\ise32.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

  • %System Root%\RESTORE

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It injects codes into the following process(es):

  • explorer.exe

Other System Modifications

This worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{Random GUID}
StubPath = %System Root%\RESTORE\{Random}\ise32.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.key
{Default} = regfile

Propagation

This worm creates the following folders in all removable drives:

  • {Removable Drive Letter}:\RESTORE

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

  • {Removable Drive Letter}:\RESTORE\{Random}\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.

Other Details

This worm connects to the following possibly malicious URL:

  • jpg.{BLOCKED}tos.us

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

7.250.07

FIRST VSAPI PATTERN DATE:

17 Jun 2010

VSAPI OPR PATTERN File:

7.251.00

VSAPI OPR PATTERN Date:

18 Jun 2010

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{Random GUID}
    • StubPath = %System Root%\RESTORE\{Random}\ise32.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.key
    • {Default} = regfile

Step 5

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.
  • {Removable Drive Letter}:\RESTORE
  • %System Root%\RESTORE

Step 6

Search and delete these files

[ 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.  
  • {Removable Drive Letter}:\autorun.inf
  • {Removable Drive Letter}:\RESTORE\{Random}\ise32.exe
  • %System Root%\RESTORE\{Random}\ise32.exe

Step 7

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