Hermes

Overview

Ransom:Win32/Hermes is a highly significant ransomware family in cybersecurity history. First appearing around 2017, Hermes gained international infamy when it was utilized by the North Korean state-sponsored threat group **Lazarus Group** as a distraction payload during the $60 million cyber-heist against the Far Eastern International Bank (FEIB) in Taiwan. Crucially, the source code and cryptographic logic of Hermes form the direct foundation of the devastating **Ryuk** ransomware, one of the most successful 'Big Game Hunting' ransomware families in existence.

Understanding the Hermes Threat
To an infected user, the outcome is catastrophic: documents, databases, and critical files are suddenly encrypted, their filenames appended with `.hermes` (or similar extensions). A ransom note (usually a `UNIQUE_ID_DO_NOT_REMOVE.html`) demands cryptocurrency. For a security operations center (SOC), a Hermes detonation represents the final stage of a highly targeted, prolonged network compromise, often indicating the presence of advanced persistent threat (APT) actors.

Execution and Encryption Mechanics
Hermes is rarely distributed via mass spam. It is deployed manually by attackers after gaining deep network access (often via compromised RDP or VPNs) (`T1133`). Once deployed via PsExec or batch scripts (`T1569.002`), the ransomware first executes a `.bat` script containing commands (like `vssadmin.exe Delete Shadows /All /Quiet`) to destroy Windows Volume Shadow Copies (`T1490`). It then rapidly encrypts targeted files (`T1486`) using a combination of RSA-2048 and AES-256 cryptography. A unique characteristic of Hermes (inherited by Ryuk) is its ability to bypass files related to the operating system boot process to ensure the victim can still boot the computer to read the ransom note.

Indicators of Compromise & Impact
The impact is severe operational downtime and potential permanent data loss. The primary IoC is the massive, rapid modification of files across the hard drive and network shares, appending the `.hermes` extension. Host-based IoCs include EDR alerts for the mass deletion of shadow copies and the execution of specific batch files used to launch the encryptor. Because it is associated with APT activity, discovering Hermes means the entire network architecture is likely compromised.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_HERMES {
    meta:
        description = "Detects Hermes (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "hermes" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Hermes Activity
id: b33a4006134bb6ee62b30fc0fac5cec6
status: experimental
description: Detects generic indicators of the hermes malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*hermes*"
    condition: selection
level: medium

Containment & Response Steps

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

1. Instantly isolate the infected endpoint from the network to halt the encryption process, explicitly disconnecting it from mapped network shares.
2. Do NOT reboot the machine immediately; capture a live memory dump (RAM) first, as forensic analysis may recover the AES key from memory.
3. Assume total network compromise. The deployment of Hermes/Ryuk indicates attackers have had domain admin access for days or weeks.
4. Wipe the infected systems and restore data from secure, immutable 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 ransom. Paying funds criminal enterprises (and potentially state-sponsored actors), and there is no guarantee the attackers will provide a working decryption tool.
2. Avoid reconnecting the machine to the network until a full forensic investigation has identified and closed the initial entry vector (e.g., compromised VPN credentials).

References & External Analysis

• Search "hermes" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Couponmarvel
• Tempedreve
• Zeleffo
• Lockcrypt
• Vopackage

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/hermes.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.