Ransomkd

Overview

Ransom:Win32/Ransomkd is a generic heuristic detection used by antivirus engines to identify executables that exhibit behavior typical of **Cryptographic Ransomware**. Because it is a generic detection, it does not identify a specific, well-known family (like Ryuk or LockBit), but rather flags the *action* of mass file encryption occurring on the system.

Understanding Ransomkd (Generic Ransomware)
To an end-user, the impact is devastating: personal documents, photos, and databases are suddenly inaccessible, appended with an unknown file extension, and a ransom note (often a `.txt` or `.hta` file) appears on the desktop demanding cryptocurrency payment for the decryption key. For a security analyst, a 'Ransomkd' detection means a severe breach has already progressed to its final, most destructive stage.

Execution and Encryption Mechanics
The delivery method varies (malspam, RDP brute-forcing, exploiting unpatched vulnerabilities). Upon execution, the malware establishes persistence (`T1547.001`) and immediately begins iterating through the file system and mapped network drives (`T1083`). It employs the Windows CryptoAPI or embedded cryptographic libraries (like AES or RSA) to rapidly encrypt files matching specific extensions (e.g., `.docx`, `.sql`, `.pdf`) (`T1486`). Crucially, to prevent easy recovery, the malware actively inhibits system recovery by deleting Volume Shadow Copies (`vssadmin.exe delete shadows`), disabling Windows Recovery Environment (`reagentc.exe /disable`), and clearing event logs (`T1490`).

Indicators of Compromise & Impact
The impact is total loss of data availability and severe business interruption. Host-based IoCs include EDR alerts for mass file modification events (high I/O activity), the execution of `vssadmin` or `bcdedit` commands by unknown processes, the appearance of ransom notes (`RESTORE_FILES.txt`), and the modification of file extensions across user directories. Network IoCs may include connections to Tor gateways or hardcoded IP addresses for key exchange prior to encryption.

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

Sigma Rule

title: Suspicious Ransomkd Activity
id: 73283a68e6d5520ce78e41e94cfbf3cf
status: experimental
description: Detects generic indicators of the ransomkd malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*ransomkd*"
    condition: selection
level: medium

Containment & Response Steps

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

1. IMMEDIATELY physically disconnect the infected endpoint from the network (pull the Ethernet cable/disable Wi-Fi) to prevent the ransomware from encrypting shared network drives and lateral movement.
2. Do not immediately reboot the machine; if the encryption process is ongoing, a reboot might finalize the destruction or trigger further payloads. Capture a live memory dump if possible to potentially recover encryption keys.
3. Identify the specific strain of ransomware (by analyzing the ransom note or file extensions) and check resources like 'No More Ransom' to see if a free decryptor exists.
4. Restore the affected systems from secure, offline backups (e.g., tape drives or immutable cloud storage) that were not accessible from the infected network.

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; it funds criminal enterprises and there is no guarantee the attackers will provide a working decryption tool.
2. Avoid reconnecting the machine to the network until it has been completely wiped and rebuilt from a known-clean image.

References & External Analysis

• Search "ransomkd" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Gentromal
• Kryptpck
• Genericrxaq
• Yakbeex
• Ufraie

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/ransomkd.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.