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TROJ_SMALL.VNI

October 09, 2012
 Analysis by: Sabrina Lei Sioting
 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 may be unknowingly downloaded by a user while visiting malicious websites.

  TECHNICAL DETAILS

File Size:

32,256 bytes

Memory Resident:

Yes

Initial Samples Received Date:

18 Dec 2011

Arrival Details

This Trojan may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops and executes the following files:

  • %Current Folder%\{parameter}

Autostart Technique

This Trojan registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_ALERTERCOM\
0000
Service = "AlerterCom"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_ALERTERCOM\
0000
ClassGUID = "{8ECC055D-047F-11D1-A537-0000F8753ED1}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AlerterCom
ImagePath = "a AlerterCom "

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AlerterCom
DisplayName = "Alerter COM Plus"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_ALERTERCOM

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_ALERTERCOM\
0000

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AlerterCom

NOTES:
This is a command line application, which creates another file in the current directory using the file name specified as parameter.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.650.06

FIRST VSAPI PATTERN DATE:

18 Dec 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

Scan your computer with your Trend Micro product and note files detected as TROJ_SMALL.VNI

Step 3

Restart in Safe Mode

[ Learn More ]

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. 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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root
    • LEGACY_ALERTERCOM
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • AlerterCom

Step 5

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.
  • %Current Folder%\{parameter}

Step 6

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