Evillocker

Overview

Executive Summary

Infection Vector and Technical Capabilities

• Volume Shadow Copy Deletion: Before encryption begins, the ransomware executes commands (e.g., `vssadmin.exe Delete Shadows /All /Quiet`) to destroy local system backups and recovery points, ensuring the victim cannot easily restore their files using Windows features.
• Strong Cryptography: It utilizes strong encryption algorithms (often a combination of AES for file encryption and RSA for key encryption) to encrypt documents, databases, images, and archives. The encrypted files are usually appended with a specific, unique extension (often `.evil` or a randomized string).
• Ransom Note Generation: A text or HTML file is dropped in every directory containing encrypted files. This note provides instructions on how to purchase cryptocurrency (usually Bitcoin) and contact the attackers to obtain the decryption key.

Threat Assessment

Incident Response and Remediation

• Immediate Network Severance: The infected endpoint must be immediately disconnected from the corporate network, Wi-Fi, and any VPNs to prevent the ransomware from propagating to mapped network drives and cloud storage sync folders.
• Preserve Memory (Do Not Reboot): If possible, capture a forensic image of the system's RAM before powering it down, as the decryption key might temporarily reside in volatile memory.
• Eradication and Restoration: Paying the ransom is strongly discouraged. The only reliable remediation strategy is a complete bare-metal wipe of the infected systems and a full restoration from secure, air-gapped backups.

Known aliases

Threat reports may refer to this family under multiple names:

• Ransom.EvilLocker
• Win32/Filecoder.Evil
• Trojan-Ransom.Win32.EvilLocker

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):

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:

rule MALWARE_WIN_EVILLOCKER_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Evillocker"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "evillocker" ascii wide nocase
        $s2 = "ransom.evillocker" ascii wide nocase
        $s3 = "win32/filecoder.evil" ascii wide nocase
        $s4 = "trojan-ransom.win32.evillocker" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Evillocker (Ransomware) Execution & Triage
id: 83d4d214-23f3-5a4b-9cfa-f3cee137d587
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Evillocker 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/evillocker
- 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.t1486
- attack.t1490
- attack.t1082
- attack.t1027
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: critical

rule MALWARE_WIN_EVILLOCKER_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Evillocker 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 = "evillocker" 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.

1. Immediately isolate affected host(s) from the internal network (disconnect physical Ethernet and disable Wi-Fi/Bluetooth) to prevent Evillocker from spreading laterally or encrypting network-attached storage (NAS) and shared SMB volumes.
2. Preserve volatile system memory (RAM capture) on a representative endpoint before attempting a reboot or power-down, as Evillocker symmetric encryption keys or uncompiled payload components may still reside in memory.
3. Audit process execution logs and terminate active scripting interpreters (e.g. PowerShell, CMD, WScript) or commands executing 'vssadmin.exe delete shadows' or 'wbadmin' used by Evillocker to inhibit recovery.
4. Investigate the initial compromise vector (such as exposed RDP instances, spearphishing attachments, or vulnerable edge gateways) and enforce an immediate credential reset for all compromised Active Directory accounts.
5. Restore critical assets and databases exclusively from verified, air-gapped, or immutable offline backups once the Evillocker binary and related persistence hooks are eradicated.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not restart or power cycle infected systems prematurely; doing so destroys volatile RAM encryption keys and may trigger bootloader locking logic embedded in Evillocker.
2. Avoid negotiating or paying the extortion demand without prior forensic evaluation and consultation with incident response specialists, as payment does not guarantee data recovery.
3. Do not connect clean backup drives or external storage to the affected network until Evillocker eradication is completely verified.

References & External Analysis

• Search "evillocker" on VirusTotal (External Analysis)
• Search "evillocker" on Any.Run (Sandbox Sandbox)
• Search "evillocker" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Amgfaohk2Uf
• Baserch
• Ruho
• Nircmd
• Qqten
• Fdoh
• Pincher
• Gatak

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/evillocker.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.