Ammyy

Overview

Ammyy (classified in antivirus detection telemetry under designations including Ransom:Win32/Ammyy, Ransom.Win32.Ammyy, and Win32/Ammyy) 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, Ammyy 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/Ammyy
• Ransom.Win32.Ammyy
• Win32/Ammyy

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.
• T1566.002: Inspect email links for known malicious domains and use link-rewriting services for time-of-click analysis.

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_AMMYY_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Ammyy"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "ammyy" ascii wide nocase
        $s2 = "ransom:win32/ammyy" ascii wide nocase
        $s3 = "ransom.win32.ammyy" ascii wide nocase
        $s4 = "win32/ammyy" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Ammyy (Ransomware) Execution & Triage
id: 60f042be-c685-5cc4-ae33-7d5b59d5c527
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Ammyy 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/ammyy
- 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_AMMYY_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Ammyy 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 = "ammyy" 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. Terminate the Ammyy Admin process immediately and isolate the machine to cut off the attacker's interactive session.
2. If the user was socially engineered into installing it, assume all credentials typed on that machine are compromised and reset them.
3. Block access to `ammyy.com` and its associated routing IPs at the enterprise perimeter firewall/proxy.
4. Use EDR to hunt for instances of `AA_*.exe` across the entire environment to ensure it hasn't been deployed laterally.

What to Avoid

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

1. Do not whitelist Ammyy Admin in your EDR/AV simply because it is a 'legitimate' tool; unless it is officially sanctioned by your IT department, it should be blocked.
2. Avoid leaving the machine on the network while investigating, as the attacker has live, interactive control.

References & External Analysis

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

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Baserch
• Brobaneup
• Cloverplus
• Fadok
• Bicololo
• Reymbz
• Mirkov
• Golroted

Machine-readable

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