Blokrypt

Category: ransomware · Aliases: Ransom.Blokrypt, Win32/Filecoder.Blokrypt, Trojan-Ransom.Win32.Blokrypt · Sample count (EMBER 2018): 1 · Enrichment: insufficient_information · Updated: 2026-07-02T06:59:32Z

Category: RansomwareActor: Unknown / CybercriminalIndustry: Global / OpportunisticMotivation: Opportunistic

Overview

Executive Summary

Blokrypt is a malicious Ransomware family designed to extort financial payment from victims by encrypting their critical data. Unlike more sophisticated "Ransomware-as-a-Service" (RaaS) operations that carefully exfiltrate data for double-extortion, Blokrypt is often deployed rapidly, prioritizing immediate, widespread encryption of local and network-mapped drives to cause maximum operational disruption.

Infection Vector and Technical Capabilities

Blokrypt is typically distributed via weaponized email attachments (spear-phishing) or deployed by threat actors who have purchased RDP credentials from Initial Access Brokers (IABs). Upon execution, Blokrypt initiates a standard but devastating attack sequence:

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.
Strong Cryptography: It utilizes strong encryption algorithms (such as AES combined with an RSA public key) to encrypt documents, databases, images, and archives. The encrypted files are usually appended with a specific, unique extension.
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

A Blokrypt infection is a critical security incident resulting in immediate and often catastrophic loss of data availability. The destruction of local backups means that without secure, offline backups, organizations face a stark choice between massive data loss or paying a criminal extortion demand.

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:

MITRE ATT&CK Techniques

This family has been observed using the following ATT&CK techniques: T1486 T1490

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

Sigma Rule

title: Suspicious Blokrypt Activity
id: 6c50c943a9ebe90d741a442c21401db6
status: experimental
description: Detects generic indicators of the blokrypt malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*blokrypt*"
            - "*ransom.blokrypt*"
            - "*win32/filecoder.blokrypt*"
            - "*trojan-ransom.win32.blokrypt*"
    condition: selection
level: medium

References & External Analysis

Search "blokrypt" on VirusTotal (External Analysis)

Frequently Asked Questions

How do I remove the Blokrypt Ransomware from Windows?

Manual removal of Blokrypt 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 Blokrypt a virus or a Ransomware?

Blokrypt is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Blokrypt typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.

What are the main symptoms of a Blokrypt infection?

Symptoms of Blokrypt 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.

Related Families (Category: ransomware)

Explore other malware families in the same category:

Protect Your Network Against Ransomwares

Want to prevent Blokrypt and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Protection Guide.

Need help with an active incident? Published by the SystemHelpdesk team.

Machine-readable

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