Where can I learn more about gandcrypt?

Refer to the linked MITRE ATT&CK technique pages, which document the behaviors associated with this family.

Gandcrypt Malware Family: IOCs, Detection, MITRE ATT&CK, Response

Overview

Executive Summary

GandCrypt (universally known as GandCrab) was one of the most prolific, destructive, and financially successful Ransomware-as-a-Service (RaaS) operations in history. First observed in January 2018, it quickly dominated the ransomware landscape, reportedly generating over $2 billion in extorted funds before its operators officially "retired" in mid-2019. It is characterized by its aggressive encryption, agile development cycles (evading security tools), and massive distribution networks.

Infection Vector and Technical Capabilities

GandCrab affiliates utilized a massive array of distribution methods. It was heavily distributed via major exploit kits (RIG, GrandSoft) and vast malspam campaigns pushed by the Necurs botnet. It was also frequently deployed manually by attackers who purchased RDP access from Initial Access Brokers (IABs). Its technical execution was highly sophisticated:

Agile Evasion and Exploitation: GandCrab underwent constant revision (from v1.0 to v5.2). Later versions famously incorporated exploits for zero-day vulnerabilities (like CVE-2018-8120 for Windows privilege escalation) and actively terminated hundreds of specific antivirus and database processes before encrypting.
Aggressive Encryption: It utilized a combination of RSA and Salsa20/AES algorithms to rapidly encrypt local files and all accessible mapped network shares. It appended various extensions to encrypted files, famously including `.GDCB`, `.CRAB`, and eventually randomized extensions.
Ransom Note and Payment: It dropped a highly recognizable ransom note (`GANDCRAB-DECRYPT.txt`) demanding payment in Dash (a privacy coin) or Bitcoin via a Tor-hosted payment portal, threatening permanent data loss if the timer expired.

Threat Assessment

A GandCrab infection is a catastrophic event resulting in immediate, massive data loss and operational downtime. While the original GandCrab operation claims to be defunct, its affiliates and tactics have migrated to modern RaaS syndicates (like REvil/Sodinokibi), and legacy or copycat infections remain a threat.

Incident Response and Remediation

Total Network Severance: If active encryption is detected, immediately pull the network cables from the infected machine(s) and critical file servers to halt the spread of the encryption across SMB shares.
Check for Free Decryptors: Because the operation officially shut down, the operators released the master decryption keys. Cybersecurity firms (like Bitdefender via NoMoreRansom.org) provide *free* decryptors for almost all versions of GandCrab. **Do not pay the ransom.**
Post-Incident Eradication: Even if data is successfully decrypted using free tools, the initial infection vector (e.g., an exposed RDP port or compromised credentials) remains open. The network must be forensically audited to close the vulnerability, and affected machines should be rebuilt from clean baselines.

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_GANDCRYPT {
    meta:
        description = "Detects Gandcrypt (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "gandcrypt" ascii wide nocase
        $s2 = "ransom.gandcrab" ascii wide nocase
        $s3 = "win32/gandcrypt" ascii wide nocase
        $s4 = "trojan-ransom.win32.gandcrypt" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Gandcrypt Activity
id: c960ab4a684244f327b26e6cf54a62ca
status: experimental
description: Detects generic indicators of the gandcrypt malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*gandcrypt*"
            - "*ransom.gandcrab*"
            - "*win32/gandcrypt*"
            - "*trojan-ransom.win32.gandcrypt*"
    condition: selection
level: medium

Gandcrypt

Overview

Executive Summary

Infection Vector and Technical Capabilities

Threat Assessment

Incident Response and Remediation

Known aliases

MITRE ATT&CK Techniques

Generated Detections (Boilerplate)

YARA Rule

Sigma Rule

References & External Analysis

Frequently Asked Questions

Related Families (Category: ransomware)

Machine-readable

Ecosystem & Interactive Environments