Analysis by: kathleenno

ALIASES:

Trojan Horse (Symantec); Trojan:Win32/Provis!rts (Microsoft); Trojan-Clicker.Win32.VB.dhu (Kaspersky); Generic.dx!mcv (Mcafee)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan, when executed, drops non-malicious files onto the infected system. It also sets attributes of its dropped .LNK files to Read-only.

  TECHNICAL DETAILS

File Size: 11,776 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 10 Mar 2011

Installation

This Trojan drops the following non-malicious files:

  • C:\Documents and Settings\All Users\Start Menu\Programs\Internet Explorer.lnk
  • %Desktop%\Internet Explorer.lnk
  • %Desktop%\Internet Explorer.url

(Note: %Desktop% is the current user's desktop, which is usually C:\Windows\Profiles\{user name}\Desktop on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Desktop on Windows NT, and C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003.)

Other System Modifications

This Trojan adds the following registry keys as part of its installation routine:

HKEY_CLASSES_ROOT\CLSID\{112FDC99-4915-4f6e-B11B-41370D5F9A1A}

NOTES:
It sets the attributes of .LNK files to Read-Only.

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 7.890.13
FIRST VSAPI PATTERN DATE: 10 Mar 2011

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

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

 
  • In HKEY_CLASSES_ROOT\CLSID
    • {112FDC99-4915-4f6e-B11B-41370D5F9A1A}

Step 3

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.
  • C:\Documents and Settings\All Users\Start Menu\Programs\Internet Explorer.lnk
  • %Desktop%\Internet Explorer.lnk
  • %Desktop%\Internet Explorer.url
  • In the Look In drop-down list, select My Computer, then press Enter.
  • Once located, select the file then press SHIFT+DELETE to permanently delete the file.
  • Step 4

    Scan your computer with your Trend Micro product to delete files detected as TROJ_CLICKER.TQ. 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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