Cometer
Table of Contents
Overview
Cometer (cataloged across security intelligence feeds under signatures such as Backdoor:Win32/Cometer, Trojan:Win32/Cometer, and Backdoor.Win32.Cometer) is a prominent remote access trojan (RAT) and backdoor closely related to the DarkComet codebase, active since 2012. Engineered to grant threat actors total interactive control over compromised Windows endpoints, Cometer is typically delivered through trojanized software downloads, weaponized file archives, and phishing emails. Once active, Cometer establishes persistence via Windows registry Run keys, opens an encrypted reverse TCP communication channel to remote command servers, and initializes surveillance modules including keystroke logging, webcam and microphone capture, live desktop streaming, remote file management, and process manipulation.
Known aliases
Threat reports may refer to this family under multiple names:
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: Darkcomet Rat Framework
Known Derivatives & Downstream Variants: Backdoor:Win32/Cometer.A · Backdoor:Win32/Cometer.B
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1056.001 · T1113 · T1125 · T1059.003 · T1547.001
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1056.001: Implement Endpoint Detection and Response (EDR) to monitor for suspicious API calls related to keystroke interception. Enforce Multi-Factor Authentication (MFA) to render stolen passwords useless.
- T1059.003: Restrict execution of Windows Command Shell (cmd.exe) and block unauthorized batch scripts.
- T1113: Monitor for frequent or unauthorized screen captures or clipboard reads. Restrict background applications from accessing desktop APIs.
- T1125: Restrict access to local camera or microphone APIs. Utilize endpoint protection that monitors hardware access.
MITRE D3FEND™ Defensive Countermeasures
Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):
| D3FEND ID | Countermeasure Name | Tactic | Countered ATT&CK | Defensive Guidance |
|---|---|---|---|---|
D3-MFA | Multi-factor Authentication | Harden | T1056.001 | Enforce FIDO2 / WebAuthn physical tokens to render keystroke-intercepted passwords useless. |
D3-PBA | Process Spawn Analysis | Detect | T1059.003 | Inspect command-line arguments and anomalous parent-child relationships spawning from cmd.exe. |
D3-SD | Screen Capture Detection | Detect | T1113 | Monitor desktop graphics API calls (BitBlt, GetDC) triggered by non-standard background threads. |
D3-HAC | Hardware Device Access Control | Isolate | T1125 | Enforce Group Policy hardware access restrictions on integrated webcams and microphones. |
D3-RPM | Registry Persistence Monitoring | Detect | T1547.001 | Audit and restrict write privileges to user and machine-level Registry Run/RunOnce keys using Endpoint Privilege Management. |
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:
Tier 1 Primitive Artifact Rule (Fast Triage)
Matches raw strings and file markers. Vulnerable to binary repacking and simple obfuscation.
rule MALWARE_WIN_COMETER_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Cometer"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "cometer" ascii wide nocase
$s2 = "backdoor:win32/cometer" ascii wide nocase
$s3 = "trojan:win32/cometer" ascii wide nocase
$s4 = "backdoor.win32.cometer" ascii wide nocase
$s5 = "win32/cometer" ascii wide nocase
$s6 = "trojan.cometer" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Tier 2 Behavioral Context Rule (Process Chains & Sigma)
Tracks parent-child process anomalies and suspicious scripting telemetry. Resilient against file renames.
title: SystemHelpDesk Detection - Cometer (Rat) Execution & Triage
id: 981fdba5-fd24-51f0-a2b5-49ccf4b2e31e
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Cometer malware family. Detects unauthorized persistence creation via Windows
Registry Run keys, scheduled tasks, and privilege escalation indicative of RAT installations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/cometer
- https://malware-families-catalog.systemhelpdesk.com/defensive/backdoor-rat-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.rat
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1056_001
- attack.t1113
- attack.t1125
- attack.t1059_003
- attack.t1547_001
logsource:
category: process_creation
product: windows
detection:
selection_process:
Image|endswith:
- \reg.exe
- \schtasks.exe
- \cmd.exe
- \powershell.exe
CommandLine|contains:
- \CurrentVersion\Run
- /create /tn
- bypass -enc
- net user /add
- net localgroup administrators
condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: highTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_COMETER_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Cometer 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 = "cometer" 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
}References & External Analysis
- Microsoft Defender Threat Encyclopedia - Backdoor:Win32/Cometer
- Trend Micro Threat Encyclopedia - Backdoor.Win32.Cometer
- Search "cometer" on VirusTotal (External Analysis)
- Search "cometer" on Any.Run (Sandbox Sandbox)
- Search "cometer" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Backdoor:Win32/Cometer?
Cometer is a remote access trojan derived from the DarkComet family that provides attackers with unauthorized remote administrative control over infected systems.
What surveillance capabilities does Cometer have?
Cometer includes keylogging, audio and webcam capture, desktop screenshots, remote shell execution, and file system exploration.
How does Cometer maintain persistence on Windows?
It writes startup entries into the CurrentVersion\Run registry keys and registers itself as a background service or startup folder shortcut.
How does Cometer communicate with its controller?
It establishes outbound reverse TCP connections over designated ports (often 1604 or 8080) using RC4-encrypted network packets.
How can systems be defended against Cometer RAT?
Deploy modern EDR solutions to detect keylogger hooks and unauthorized camera activations, restrict execution of unknown executables, and block anomalous outbound TCP ports.
How do I remove Cometer from Windows?
Manual removal of Cometer is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
What are the main symptoms of a Cometer infection?
Symptoms of Cometer can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Protect Your Network Against Rats
Want to prevent Cometer and similar threats from compromising your organization? Read our comprehensive defensive guide: Backdoor & RAT Protection for Businesses.
📣 Threat Intel Correction or Update?
Notice an outdated IOC, unlisted alias, or disputed attribution? Threat researchers are invited to propose an update on GitHub or contact the SystemHelpDesk research desk. All community revisions are credited in our public CHANGELOG.
Machine-readable
Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/cometer.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.