Analysis by: Leidryn Saludez
ALIASES:

Trojan-Ransom.Win32.Agent.baao (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

This Ransomware 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 propagation routine.

It does not have any backdoor routine.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 79,872 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 09 Jan 2026
Payload: Drops files, Adds process

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • {Encrypted Directory}\help_decrypt.vbs → audible spoken warnings
  • {Encrypted Directory}\help_decrypt.img

It adds the following processes:

  • "%System%\wscript.exe" {Encrypted Directory}\help_decrypt.vbs → It plays an audible message stating "“Warning!, I have encrypted files in your demo folder and sub-folders!”

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Propagation

This Ransomware does not have any propagation routine.

Backdoor Routine

This Ransomware does not have any backdoor routine.

Rootkit Capabilities

This Ransomware does not have rootkit capabilities.

Other Details

This Ransomware encrypts files with the following extensions:

  • .pptx
  • .xlsx

It does the following:

  • It encrypts files found in the given path.
  • If there's no given path to encrypt, the default path to encrypt is C:\demo.

It accepts the following parameters:

  • {Path to Encrypt} → specific path to encrypt

It does not exploit any vulnerability.

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • .encrypted!

It drops the following file(s) as ransom note:

  • {Encrypted Directory}\help_decrypt.html

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.784.08
FIRST VSAPI PATTERN DATE: 16 Jun 2021
VSAPI OPR PATTERN File: 16.785.00
VSAPI OPR PATTERN Date: 17 Jun 2021

Step 1

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 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

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.
  • {Encrypted Directory}\help_decrypt.vbs
  • {Encrypted Directory}\help_decrypt.html
  • {Encrypted Directory}\help_decrypt.img

Step 4

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.WASTST.SM. 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:

Step 5

Restore encrypted files from backup.


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