Lockcrypt

Overview

Ransomware:Win32/Lockcrypt is a destructive ransomware family that encrypts user data and demands payment for the decryption key. Unlike 'spray-and-pray' ransomware distributed via massive spam campaigns, Lockcrypt is frequently deployed manually by attackers who have already compromised the target network, often via brute-forced RDP (Remote Desktop Protocol) connections (`T1133`).

Understanding Lockcrypt
To an end-user, Lockcrypt is devastating; their files become inaccessible, their extensions are altered (often to `.lock`), and a ransom note appears on the desktop demanding cryptocurrency. For an incident response team, a Lockcrypt infection signifies a total breach of the network perimeter. The attackers had interactive access, navigated the network, likely escalated privileges, and manually executed the ransomware payload across multiple systems simultaneously (`T1486`).

Execution and Encryption Mechanics
Initial access is often achieved by scanning the internet for exposed RDP ports (TCP 3389) and brute-forcing weak credentials (`T1110.001`). Once inside, the attackers disable endpoint security tools (`T1562.001`) and use tools like PsExec to distribute the Lockcrypt payload. Upon execution, Lockcrypt terminates processes associated with databases (SQL, Exchange) to ensure those files are unlocked and available for encryption (`T1489`). It deletes Volume Shadow Copies (`vssadmin.exe delete shadows`) (`T1490`) to prevent easy recovery. It then encrypts files using strong cryptography, appending a specific extension to the locked files, and drops a ransom note (e.g., `Restore_Files.txt`).

Indicators of Compromise & Impact
The primary impact is the complete loss of data availability and severe business disruption. Host-based IoCs include the presence of the encrypted files, the ransom note, event logs showing the deletion of Shadow Copies, and EDR alerts for the manual execution of the ransomware binary (often from a temp directory or desktop). Network IoCs are critical for tracing the initial access: look for massive amounts of failed RDP login attempts followed by a successful login from a foreign IP address.

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

Sigma Rule

title: Suspicious Lockcrypt Activity
id: 7e1ad526faaf6c09c84392c0b2260641
status: experimental
description: Detects generic indicators of the lockcrypt malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*lockcrypt*"
    condition: selection
level: medium

Containment & Response Steps

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

1. Immediately isolate affected machines from the network to prevent the ransomware from encrypting mapped network drives.
2. Identify and sever the attacker's point of entry; if RDP was exposed to the internet, disable the port at the firewall immediately.
3. Do not reboot infected servers if possible; capture a live memory image (RAM dump), as the encryption keys might still reside in memory.
4. Initiate the organization's Disaster Recovery (DR) plan; restore data from offline, immutable 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 there is no guarantee the attackers will provide a working decryptor.
2. Avoid exposing RDP (TCP 3389) directly to the internet; always mandate VPN access and MFA for remote administration.

References & External Analysis

• Search "lockcrypt" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Upadter
• Trick
• Alreay
• Plimrost
• Reset

Machine-readable

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