Lockcrypt
Table of Contents
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 our technical analysis hubs and the official MITRE ATT&CK framework:
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-FAED | File Alteration Early Detection | Detect | T1486 | Deploy canary files and monitor mass rename/encryption I/O spikes to terminate ransomware threads immediately. |
D3-VSS | Volume Shadow & Snapshot Hardening | Harden | T1490 | Block execution of vssadmin.exe and wmic shadowcopy delete; maintain air-gapped immutable backup repositories. |
D3-STA | Security Tool Anti-Tamper Enforcement | Harden | T1562.001 | Block unauthorized modification of antivirus registry flags and prevent stopping security agent services. |
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_LOCKCRYPT_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Lockcrypt"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "lockcrypt" 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 - Lockcrypt (Ransomware) Execution & Triage
id: 187e0e9c-65d0-532b-a6c4-e2a2d62cdc14
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Lockcrypt malware family. Detects volume shadow copy deletion, boot status
tampering, and recovery inhibition characteristic of modern ransomware operations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/lockcrypt
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-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.ransomware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1133
- attack.t1486
- attack.t1490
- attack.t1562_001
logsource:
category: process_creation
product: windows
detection:
selection_process:
Image|endswith:
- \vssadmin.exe
- \wmic.exe
- \wbadmin.exe
- \bcdedit.exe
CommandLine|contains:
- delete shadows
- shadowcopy delete
- resize shadowstorage
- recoveryenabled no
- ignoreallfailures
condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: criticalTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_LOCKCRYPT_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Lockcrypt 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 = "lockcrypt" 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
}Containment & Response Steps
Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.
- Immediately isolate affected machines from the network to prevent the ransomware from encrypting mapped network drives.
- Identify and sever the attacker's point of entry; if RDP was exposed to the internet, disable the port at the firewall immediately.
- Do not reboot infected servers if possible; capture a live memory image (RAM dump), as the encryption keys might still reside in memory.
- 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.
- Do not pay the ransom. Paying funds criminal enterprises and there is no guarantee the attackers will provide a working decryptor.
- 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)
- Search "lockcrypt" on Any.Run (Sandbox Sandbox)
- Search "lockcrypt" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Lockcrypt and what threat category does it belong to?
Lockcrypt is classified as a Ransomware. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments.
How does Lockcrypt establish persistence and evade defensive controls?
Lockcrypt typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks.
What are the essential incident response steps for mitigating a Lockcrypt compromise?
Security teams responding to Lockcrypt should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups.
What cryptographic algorithms and file targeting techniques does Lockcrypt employ during execution?
Lockcrypt typically leverages hybrid cryptographic architectures combining symmetric stream or block ciphers (such as AES-256 or ChaCha20) for rapid file encryption with asymmetric algorithms (such as RSA-2048 or Curve25519) to securely protect the session keys. It aggressively targets sensitive file extensions including corporate documents, databases, virtual disks, and backups while systematically executing commands to delete Volume Shadow Copies (vssadmin delete shadows /all /quiet) and disable system recovery options.
Are decryptors available for Lockcrypt, and what is the recommended recovery procedure?
Decryption availability for Lockcrypt depends on whether security researchers or law enforcement (such as the No More Ransom initiative) have recovered the master private keys or discovered flaws in its key generation routines. Victims should never pay the extortion demand, as payment fuels criminal operations without guaranteeing file restoration. The recommended recovery procedure entails isolating infected hosts, conducting forensic disk imaging, identifying the root access vector, and restoring validated systems from immutable offline backups.
How do I remove the Lockcrypt Ransomware from Windows?
Manual removal of Lockcrypt 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.
Is Lockcrypt a virus or a Ransomware?
Lockcrypt is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Lockcrypt typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Lockcrypt infection?
Symptoms of Lockcrypt 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 Ransomwares
Want to prevent Lockcrypt and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Containment & Incident Response.
📣 Threat Intel Correction or Update?
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Ecosystem & Interactive Environments
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