Enigma

Overview

Enigma (classified as Ransom:Win32/Enigma and Trojan-Ransom.Win32.Enigma) is an advanced Windows crypto-ransomware family designed for rapid and devastating corporate extortion. Distributed through malicious email spam containing weaponized HTML attachments and compromised RDP connections, Enigma initiates execution by checking system language and locale settings to avoid infecting Commonwealth of Independent States (CIS) endpoints. It uses strong symmetric encryption (AES-128 in CBC mode or ChaCha20) combined with an embedded RSA public key to encrypt user files, appending .enigma to encrypted files. It generates comprehensive HTML ransom notes (enigma.html), deletes Volume Shadow Copies with vssadmin, and directs victims to a Tor negotiation portal.

Known aliases

Threat reports may refer to this family under multiple names:

• Ransom:Win32/Enigma
• Trojan-Ransom.Win32.Enigma
• Win32/Enigma
• Enigma Ransomware
• Ransom.Enigma

MITRE ATT&CK Techniques

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

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_ENIGMA_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Enigma"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "enigma" ascii wide nocase
        $s2 = "ransom:win32/enigma" ascii wide nocase
        $s3 = "trojan-ransom.win32.enigma" ascii wide nocase
        $s4 = "win32/enigma" ascii wide nocase
        $s5 = "enigma ransomware" ascii wide nocase
        $s6 = "ransom.enigma" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Enigma (Ransomware) Execution & Triage
id: 0c3e8e0d-93b4-5792-bf02-3fde28889e88
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Enigma 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/enigma
- 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.t1614_001
- attack.t1027_006
- attack.t1083
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_ENIGMA_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Enigma 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 = "enigma" 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. Isolate the endpoint immediately; the successful execution of an Enigma-packed file usually results in an active ransomware or trojan infection.
2. Capture a live memory image (RAM dump); this is often the only way to recover the unencrypted payload for reverse engineering and IoC extraction.
3. Utilize EDR telemetry to trace the origin of the packed executable to identify the initial infection vector (e.g., a phishing email or drive-by download).
4. Do not rely on standard AV scans to clean the machine, as the unpacked payload may have established secondary persistence mechanisms.

What to Avoid

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

1. Avoid assuming an executable is safe just because it passes a static antivirus scan; heavily packed files are designed specifically to bypass these checks.
2. Do not attempt to manually reverse engineer the Enigma stub without specialized unpacking tools; commercial protectors are highly complex and time-consuming to defeat.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Ransom:Win32/Enigma
• Kaspersky Threat Intelligence - Trojan-Ransom.Win32.Enigma
• MITRE ATT&CK - Data Encrypted for Impact (T1486)
• Search "enigma" on VirusTotal (External Analysis)
• Search "enigma" on Any.Run (Sandbox Sandbox)
• Search "enigma" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Xxycff
• Emudbot
• Blacoleref
• Dlsecure
• Sahat
• Ilomo
• Mi0Ax8Mhb4Ji
• Zonebac

Machine-readable

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