Samas

Overview

Ransom:Win32/Samas (infamously known as **SamSam** or MSIL/Samas) is a highly destructive, targeted ransomware family that gained notoriety for crippling major hospitals and municipal governments (such as the City of Atlanta). Unlike opportunistic ransomware (like WannaCry or Locky) that rely on massive, automated spam campaigns or worms, SamSam is characterized by its **manual deployment**. Threat actors actively breach a specific target network, map the infrastructure, steal credentials, and then manually execute the SamSam payload across all critical servers simultaneously to maximize extortion leverage.

Understanding the SamSam Threat
To an organization, a SamSam attack is the culmination of a severe, prolonged security breach. The actors behind SamSam (often attributed to Iranian state-sponsored groups) meticulously choose their targets based on their ability to pay massive ransoms. Because the deployment is human-driven, they deliberately target database servers, backup servers, and domain controllers, ensuring the organization cannot easily recover.

Execution and Targeted Encryption Mechanics
The initial breach usually occurs via exploiting vulnerable public-facing servers (like JBoss) (`T1190`) or brute-forcing weak RDP credentials (`T1133`). Once inside, the attackers use tools like Mimikatz or Lazagne to dump Domain Admin credentials (`T1003`). They then use legitimate administrative tools like PsExec or WMI (`T1047`) to distribute the SamSam `.exe` across the network (`T1105`). When executed, SamSam utilizes strong RSA-2048 and AES-256 encryption (`T1486`), specifically targeting hundreds of file extensions associated with critical business data. It appends extensions like `.weapologize` or `.samas` and drops a ransom note instructing victims to visit a Tor hidden service.

Indicators of Compromise & Impact
The primary impact is a total halt of business operations and critical services. Host-based IoCs include EDR alerts for the execution of the SamSam binary (which is often heavily obfuscated .NET code) via `PsExec.exe`, and the mass renaming of files. The presence of the `HELP_DECRYPT_YOUR_FILES.html` ransom note is a definitive indicator. Network IoCs include anomalous lateral movement (SMB/RPC traffic) originating from a compromised internal server.

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:

• T1003: Monitor for LSASS memory dumping or registry SAM extraction. Enable Credential Guard on Windows systems.

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_SAMAS_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Samas"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "samas" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Samas (Ransomware) Execution & Triage
id: 70f33c2b-d6c3-552f-9b74-f3f53b82ca0e
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Samas 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/samas
- 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.t1133
- attack.t1486
- attack.t1047
- attack.t1003
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_SAMAS_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Samas 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 = "samas" 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. Immediately sever the entire infected subnet from the wider network to prevent the manual lateral movement of the ransomware.
2. Identify the 'Patient Zero' entry point (e.g., the exposed RDP server or unpatched JBoss server) and immediately take it offline to cut the attacker's access.
3. Do not restart the infected servers, as this may destroy forensic evidence in RAM or trigger secondary destructive payloads.
4. Initiate a full Incident Response investigation; the presence of SamSam means a human attacker has had Domain Admin access to your network.

What to Avoid

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

1. Do not assume this is a standard, automated virus infection; SamSam attacks are targeted and interactive, requiring a 'hands-on-keyboard' response.
2. Avoid paying the ransom unless absolutely necessary for human safety (e.g., in a hospital setting); the FBI strongly discourages funding these specific threat groups.

References & External Analysis

• Search "samas" on VirusTotal (External Analysis)
• Search "samas" on Any.Run (Sandbox Sandbox)
• Search "samas" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Netthief
• Tnega
• Retribution
• Hc4Cakjs5Bhi
• Winner
• Killnotes
• Pres
• Kbot

Machine-readable

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