Blihan

Overview

Blihan (classified in endpoint telemetry as Ransom:Win32/Blihan, Trojan-Ransom.Win32.Blihan, and Win32/Blihan) is an aggressive crypto-ransomware family designed to extort Windows organizations and individual users. Distributed through spearphishing email campaigns, malicious office macros, and fake software installers, Blihan initiates rapid directory traversal upon execution. It targets high-value user data, including financial spreadsheets, contracts, databases, and system backups, locking them with robust symmetric and asymmetric encryption algorithms (such as AES paired with RSA). Blihan appends a unique extension (such as .blihan) to encrypted files, executes vssadmin delete shadows /all /quiet to purge Volume Shadow Copies, and deposits ransom notes detailing payment instructions in Bitcoin or Monero.

Known aliases

Threat reports may refer to this family under multiple names:

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

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_BLIHAN_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Blihan"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "blihan" ascii wide nocase
        $s2 = "ransom:win32/blihan" ascii wide nocase
        $s3 = "trojan-ransom.win32.blihan" ascii wide nocase
        $s4 = "win32/blihan" ascii wide nocase
        $s5 = "ransom.blihan" ascii wide nocase
        $s6 = "ransom:win32/blihan.a" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Blihan (Ransomware) Execution & Triage
id: aea4e89b-912c-5ac5-9856-c93614c34441
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Blihan 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/blihan
- 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_BLIHAN_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Blihan 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 = "blihan" 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 network segments immediately to prevent encryption spreading across shares.
2. Kill active ransomware processes using Task Manager or elevated PowerShell commands.
3. Capture memory dumps and binary samples for malware analysis and IOC attribution.
4. Block delivery domains and malicious sender email addresses at perimeter firewalls.
5. Restore files from air-gapped, immutable backup archives.

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 cybercrime without guaranteeing decryption key delivery.
2. Do not connect backup storage media to affected computers before ensuring the system is clean.

References & External Analysis

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

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Adagent
• Begseabug
• Banz
• Food
• Opesup
• Cloxer
• Dishigy
• Offtoup

Machine-readable

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