Tonmye

Overview

Tonmye (tracked across antimalware research as Ransom:Win32/Tonmye, Trojan-Ransom.Win32.Tonmye, and Win32/Tonmye) is a destructive crypto-ransomware family targeting Windows systems. Infiltrating endpoints through malicious phishing email attachments, exploit kits, and compromised software repacks, Tonmye initiates system discovery upon execution. It terminates database management engines, productivity applications, and backup software using command-line taskkill to unlock open files. Tonmye enumerates local hard drives, removable USB storage, and connected network shares, encrypting documents, databases, archives, and multimedia files using AES-256 encryption wrapped with an embedded RSA public key. To impede file restoration, Tonmye executes shell commands invoking vssadmin to delete Volume Shadow Copies and uses bcdedit to disable automatic startup recovery, before displaying desktop extortion instructions demanding cryptocurrency payment.

Known aliases

Threat reports may refer to this family under multiple names:

• Ransom:Win32/Tonmye
• Trojan-Ransom.Win32.Tonmye
• Win32/Tonmye
• Ransom.Tonmye
• Ransom:Win32/Tonmye.A

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1566.001: Scan email attachments for malicious macros, scripts, or suspicious archive files.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_TONMYE_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Tonmye"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "tonmye" ascii wide nocase
        $s2 = "ransom:win32/tonmye" ascii wide nocase
        $s3 = "trojan-ransom.win32.tonmye" ascii wide nocase
        $s4 = "win32/tonmye" ascii wide nocase
        $s5 = "ransom.tonmye" ascii wide nocase
        $s6 = "ransom:win32/tonmye.a" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Tonmye (Ransomware) Execution & Triage
id: 125cff25-b8a7-5f23-ba1a-073fd9b49d8f
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Tonmye malware family. Detects volume shadow copy deletion, boot status
  tampering, and recovery inhibition characteristic of modern ransomware operations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/tonmye
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.ransomware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1486
- attack.t1490
- attack.t1566_001
- attack.t1083
- attack.t1070_004
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \vssadmin.exe
    - \wmic.exe
    - \wbadmin.exe
    - \bcdedit.exe
    CommandLine|contains:
    - delete shadows
    - shadowcopy delete
    - resize shadowstorage
    - recoveryenabled no
    - ignoreallfailures
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: critical

rule MALWARE_WIN_TONMYE_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Tonmye tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "tonmye" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Immediately sever the network connection of affected hosts to halt encryption across shared network drives.
2. Kill active ransomware processes via Windows Task Manager or elevated PowerShell commands.
3. Preserve forensic memory dumps and sample files for threat intelligence and IOC documentation.
4. Block malicious delivery domains and sender email addresses at perimeter firewalls.
5. Rebuild compromised endpoints from verified clean master images and restore data from offline backups.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not pay the cryptocurrency extortion demand; payment does not guarantee decryption key recovery.
2. Do not reboot systems before securing volatile forensic memory data.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Ransom:Win32/Tonmye
• Trend Micro Threat Encyclopedia - Ransom_Tonmye
• Kaspersky Threat Intelligence Portal - Trojan-Ransom.Win32.Tonmye
• Search "tonmye" on VirusTotal (External Analysis)
• Search "tonmye" on Any.Run (Sandbox Sandbox)
• Search "tonmye" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Bnuaaewgb2Fb
• Rogan
• Axbn
• Ghoul
• Pulobe
• Wmqarhe5P8Fbt
• Diss
• Crypt0L0Cker

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/tonmye.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.