Antavmu

Overview

Antavmu (classified in antivirus detection telemetry under designations including Ransom:Win32/Antavmu, Ransom.Win32.Antavmu, and Win32/Antavmu) is a crypto-ransomware designed to locate, encrypt, and hold hostage high-value user documents, database stores, and system files. Disseminated across enterprise networks and consumer workstations via social engineering, phishing attachments, malicious drive-by downloads, or weaponized software cracks, Antavmu executes an initial reconnaissance phase upon system ingress. The binary evaluates host privileges, detects active hypervisors and sandbox environments to evade behavioral analysis, and establishes resilient autostart persistence by configuring registry keys under HKCU\Software\Microsoft\Windows\CurrentVersion\Run or registering background Windows services. Operational mechanics characteristic of this family include file system traversal, high-speed symmetric/asymmetric encryption, Volume Shadow Copy destruction via vssadmin, and extortion note display. Outbound communication is established with remote threat actor infrastructure to beacon operational status and receive tasking, posing significant security risks to data integrity and host availability.

Known aliases

Threat reports may refer to this family under multiple names:

• Ransom:Win32/Antavmu
• Ransom.Win32.Antavmu
• Win32/Antavmu

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:

• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

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_ANTAVMU_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Antavmu"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "antavmu" ascii wide nocase
        $s2 = "ransom:win32/antavmu" ascii wide nocase
        $s3 = "ransom.win32.antavmu" ascii wide nocase
        $s4 = "win32/antavmu" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Antavmu (Ransomware) Execution & Triage
id: 404e6ba0-e591-56b4-9661-754190375072
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Antavmu 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/antavmu
- 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.t1489
- attack.t1547_001
- attack.t1083
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_ANTAVMU_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Antavmu 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 = "antavmu" 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. Instantly isolate the endpoint from the network; if Antavmu is active, a severe secondary deployment (like ransomware) is likely imminent.
2. Do not rely on the local EDR agent for containment if Antavmu was successful; isolate the machine at the switch/firewall level.
3. Capture a memory dump (RAM) immediately. The disabler module and the subsequent payload are likely active in memory even if the EDR is blind.
4. Perform a deep forensic review to identify the initial entry vector that allowed Antavmu to gain execution privileges.

What to Avoid

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

1. Do NOT assume the endpoint is safe if you simply restart the antivirus service; the malware maintains persistence and will disable it again.
2. Avoid relying solely on automated remediation; a successful Antavmu attack means the automated tools have been compromised.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Ransom:Win32/Antavmu
• Kaspersky Threat Intelligence - Ransom.Win32.Antavmu
• MITRE ATT&CK - Enterprise Techniques
• Search "antavmu" on VirusTotal (External Analysis)
• Search "antavmu" on Any.Run (Sandbox Sandbox)
• Search "antavmu" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Globeimposter
• Rifbu
• Magic
• Gracewire
• Startserv
• Tikoog
• Xmgfbs8Lpqoib
• Puamson

Machine-readable

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