Analysis by: John Rainier Navato
 Modified by: Neljorn Nathaniel Aguas

ALIASES:

Virus:X97M/Laroux.A (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Virus

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware, Dropped by specific malware

This Virus arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any backdoor routine.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size: 546,304 bytes
File Type: XLS
Memory Resident: No
Initial Samples Received Date: 09 May 2024

Arrival Details

This Virus 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 Virus drops a copy of itself in the following folders using different file names:

  • {Excel Application Path}\XLSTART\mypersonnel.xls → if the malware file is not executed in this location.

Backdoor Routine

This Virus does not have any backdoor routine.

Rootkit Capabilities

This Virus does not have rootkit capabilities.

Information Theft

This Virus does not have any information-stealing capability.

Other Details

This Virus does the following:

  • It disables the Escape key to prevent users from cancelling the script's execution.
  • It checks for the following conditions:
    • If the file is in ".xlsx" format.
    • If the version of the file is Microsoft Office Excel 2007 or newer.
  • If one of the conditions is met, it will create a copy of itself with the following filename and version and deletes the original file afterwards:
    • {Malware Path}\{Malware Name}.xls → file version set to Microsoft Excel 97-2003
  • It remains active every time Excel is launched, infecting any new workbooks created and previously saved workbooks when they are opened.
  • If the first sheet is not named "Kangatang", it copies a sheet named "Kangatang" containing the malicious script to the beginning of the active workbook to ensure infection and propagation.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.332.05
FIRST VSAPI PATTERN DATE: 10 May 2024
VSAPI OPR PATTERN File: 19.333.00
VSAPI OPR PATTERN Date: 11 May 2024

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

    • Downloader.VBA.TRX.XXVBAF01FF052

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

Search and delete this file

[ 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.  
  • {Excel Application Path}\XLSTART\mypersonnel.xls

Step 4

Scan your computer with your Trend Micro product to delete files detected as Virus.X97M.LAROUX.F. 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 the following Trend Micro Support pages for more information:


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