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WORM_HAMWEQ.DN

February 20, 2013
 Modified by: Roland Marco Dela Paz
 ALIASES:

W32/Hamweq.worm.y (Mcafee); Worm:Win32/Hamweq.gen!C (Microsoft)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via removable drives


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.

It connects to a website to send and receive information. It may also connect to Internet Relay Chat (IRC) servers and receive commands from a remote user.

  TECHNICAL DETAILS

File Size:

286,720 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

25 Apr 2012

Payload:

Connects to URLs/IPs, Compromises system security

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:

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

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

It drops the following non-malicious file:

  • %System Root%\CONFIG\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 creates the following folders:

  • %System Root%\CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013
  • %System Root%\CONFIG

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

It injects itself into the following processes as part of its memory residency routine:

  • explorer.exe

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-AAX5-21CX3C644241}
StubPath = "%System Root%\CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013\usr.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_CLASSES_ROOT\.key

Propagation

This worm creates the following folders in all removable drives:

  • {removable drive letter}:\CONFIG\
  • {removable drive letter}:\CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013

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

  • [DRIVE]:\CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013\usr.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=CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013\usr.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013\usr.exe
shell\open\default=1

Backdoor Routine

This worm connects to the following websites to send and receive information:

  • uxp.{BLOCKED}s.as

It may also connect to Internet Relay Chat (IRC) servers and receive commands from a remote user.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.938.06

FIRST VSAPI PATTERN DATE:

25 Apr 2012

VSAPI OPR PATTERN File:

8.939.00

VSAPI OPR PATTERN Date:

25 Apr 2012

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

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}:\CONFIG\
  • {removable drive letter}:\CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013
  • %System Root%\CONFIG
  • %System Root%\CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013

Step 4

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_CLASSES_ROOT
    • .key
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {28ABC5C0-4FCB-11CF-AAX5-21CX3C644241}

Step 5

Search and delete AUTORUN.INF files created by WORM_HAMWEQ.DN that contain these strings

[ Learn More ]
[autorun]
open=CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013\usr.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=CONFIG\S-1-5-21-1482476501-1644491937-682003330-1013\usr.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_HAMWEQ.DN . 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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