Krucky

Overview

Krucky (tracked in malware research telemetry under designations including Ransom:Win32/Krucky, Ransom:Win32/Krucky.A, and Trojan-Ransom.Win32.Krucky) is a destructive crypto-ransomware family targeting Windows endpoints. Operating in opportunistic extortion campaigns, Krucky infiltrates target networks via malicious email campaigns containing obfuscated JavaScript or VBScript droppers and through compromised software cracks. Upon execution, Krucky terminates security processes and database engines using taskkill. It searches mounted fixed disks, removable drives, and accessible network SMB shares, encrypting documents, spreadsheets, SQL databases, and archives using AES-256 encryption with an embedded RSA public key. Krucky disables system recovery by executing vssadmin to delete Volume Shadow Copies and uses bcdedit to disable automatic Windows startup recovery. It leaves text ransom notes in every traversed directory instructing victims on Bitcoin extortion demands.

Known aliases

Threat reports may refer to this family under multiple names:

• Ransom:Win32/Krucky
• Ransom:Win32/Krucky.A
• Trojan-Ransom.Win32.Krucky
• Win32/Krucky
• Ransom.Krucky

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1566.001: Scan email attachments for malicious macros, scripts, or suspicious archive files.

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_KRUCKY_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Krucky"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "krucky" ascii wide nocase
        $s2 = "ransom:win32/krucky" ascii wide nocase
        $s3 = "ransom:win32/krucky.a" ascii wide nocase
        $s4 = "trojan-ransom.win32.krucky" ascii wide nocase
        $s5 = "win32/krucky" ascii wide nocase
        $s6 = "ransom.krucky" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Krucky (Ransomware) Execution & Triage
id: f5af6a68-efe6-5743-aac6-b2b25cb90bb4
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Krucky 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/krucky
- 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.t1566_001
- attack.t1083
- attack.t1070_004
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_KRUCKY_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Krucky 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 = "krucky" 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. Disconnect the affected host from all physical and wireless network interfaces to halt encryption.
2. Kill active ransomware processes using Task Manager or command-line commands.
3. Preserve system memory dumps and sample files for threat intelligence and forensics.
4. Block malicious sender domains and network indicators at border firewalls.
5. Rebuild infected machines and restore files from verified offline 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 cryptocurrency ransom demand; it funds illicit cybercrime activities without guarantee of recovery.
2. Do not connect clean backup drives to machines before verifying they are thoroughly remediated.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Ransom:Win32/Krucky
• Trend Micro Threat Encyclopedia - Ransom_Krucky
• Kaspersky Threat Intelligence Portal - Trojan-Ransom.Win32.Krucky
• Search "krucky" on VirusTotal (External Analysis)
• Search "krucky" on Any.Run (Sandbox Sandbox)
• Search "krucky" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Yobdam
• Aspm
• Pjtbinder
• Oflwr
• Darkside
• Etap
• Myxah
• Betload

Machine-readable

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