Coma

Overview

The Coma virus is a vintage MS-DOS file infector known for its simplistic yet disruptive payload. Operating as a non-resident parasitic virus, Coma searches the current directory for uninfected .COM executables whenever an infected file is executed. Upon locating a suitable target, it appends its relatively small viral code to the end of the file and modifies the header to redirect the initial execution flow to the virus body. The virus earns its name from its disruptive payload: under specific, pseudo-random conditions tied to the system clock or execution count, Coma attempts to halt the system or place it into an unresponsive state, essentially putting the machine in a coma. While lacking advanced polymorphic encryption or stealth techniques, Coma represents the early days of malware development where direct file modification and immediate, visible disruption were the primary goals of virus authors. It is effectively extinct in modern environments.

Known aliases

Threat reports may refer to this family under multiple names:

• DOS.Coma

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Win32_Parasitic_Pe_Virus

Known Derivatives & Downstream Variants: Win32.Coma.3200 · Virus.Win32.Coma

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):

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• 0a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b
• 1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c

Delivery vectors

• Infected executable file distribution via peer-to-peer file sharing networks
• Lateral propagation across accessible network shares hosting executable files

Persistence mechanisms

• Section addition and entry point redirection in infected PE files on local drives
• Hooking kernel file I/O APIs to infect newly accessed executables

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_COMA_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Coma"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "coma" ascii wide nocase
        $s2 = "dos.coma" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Coma (File Infector) Execution & Triage
id: d2871eb4-8660-5309-9a23-8b0d7a68f5bc
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Coma malware family. Detects suspicious execution from temporary user directories
  with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/coma
- 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.file-infector
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1485
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \cscript.exe
    - \wscript.exe
    CommandLine|contains:
    - AppData\Local\Temp
    - -WindowStyle Hidden
    - /e:jscript
    - bitsadmin /transfer
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: medium

rule MALWARE_WIN_COMA_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Coma 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 = "coma" 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 affected endpoints from the network immediately to sever unauthorized command and control communication.
2. Identify and terminate active Coma binaries and associated parent-child process chains.
3. Audit persistence vectors including Registry Run keys, Scheduled Tasks, and services for unauthorized entries.
4. Collect forensic disk and memory triage artifacts before conducting system re-imaging.

What to Avoid

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

1. Do not attempt manual string or file deletion while network connections remain active; this can trigger secondary dropper routines.
2. Avoid restoring from backups without verifying that the backup snapshot predates initial Coma installation.

References & External Analysis

• Trend Micro Threat Encyclopedia - PE_COMA.A Analysis
• Kaspersky Virus Encyclopedia - Virus.Win32.Coma
• Search "coma" on VirusTotal (External Analysis)
• Search "coma" on Any.Run (Sandbox Sandbox)
• Search "coma" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: File Infector)

Explore other documented threats in the same operational category:

• Alman
• Fujacks
• Viking
• Invader
• Virut
• Yuner
• Neshta
• Expiro

Machine-readable

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