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 the 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.

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_SAMAS {
    meta:
        description = "Detects Samas (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "samas" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Samas Activity
id: 31f6684cb18648519f8540c9d4f32266
status: experimental
description: Detects generic indicators of the samas malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*samas*"
    condition: selection
level: medium

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)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Candybox
• Boxter
• Avira
• Winexec
• Jobcrypter

Machine-readable

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