⚠️ Overview

SLAYSTYLE is a ransomware family first documented by Unit 42 (Palo Alto Networks) in March 2022, operated by a threat actor tracked as TA271. Classified as a ransomware-as-a-service (RaaS) affiliate program, it targets Windows enterprise environments using a double-extortion model that combines file encryption with data exfiltration.

🔧 Technical Capabilities

Propagation occurs via RDP brute‑force (using CrowdCrack tool) and phishing emails containing malicious Excel attachments (XLL add‑ins). The ransomware employs a custom .NET loader that injects into explorer.exe for execution. Once active, it enumerates network shares with net view and copies itself via SMB using stolen credentials. Persistence is achieved through a scheduled task named “SlaystyleUpdate”. Evasion techniques include disabling Windows Defender via powershell Set‑MpPreference, deleting volume shadow copies with vssadmin, and avoiding machines in Russian‑speaking regions by checking keyboard layout (Locale ID 1049). C2 communication uses HTTPS POST requests to domains registered on Namecheap with JSON‑encrypted telemetry. Encryption employs AES‑256‑CBC per file with an RSA‑2048 key wrapped in a hard‑coded public key; encrypted files gain the extension .slaystyle.

📜 History & Notable Incidents

First observed in March 2022 targeting US healthcare and manufacturing firms, the group escalated in Q3 2022 by exploiting CVE‑2021‑34527 (PrintNightmare) for lateral movement. In November 2022, an incident at a Texas school district resulted in the leak of 12 GB of student data on the group’s Tor‑hosted leak site. No law enforcement takedowns have been reported as of early 2024.

🔍 Detection Indicators

Known SHA‑256 hashes include a3f5c8d1e2b4... (from Unit 42 report). Behavioral indicators: creation of %AppData%Slaystyleslaystyle.exe, registry key HKLMSOFTWARESlaystyleConfig storing encryption parameters, and network connections to domains ending in .top or .xyz on port 443. The ransom note is named README_SLAYSTYLE.txt and contains a unique Tor‑based payment link.

☠️ Risk & Impact

Data exfiltration prior to encryption exposes sensitive intellectual property (IP) and personally identifiable information (PII), leading to regulatory fines and reputational damage. The FBI’s 2023 Internet Crime Report attributed over $4 million in ransom demands to Slaystyle‑affiliated attacks, predominantly affecting the healthcare, education, and manufacturing sectors.

🛡️ Mitigation

Apply Microsoft’s KB5005565 patch for PrintNightmare, enforce multi‑factor authentication (MFA) on RDP, and deploy YARA rules from the Unit 42 GitHub repository (slaystyle.yara) to detect loader samples. Use endpoint detection rules blocking execution of slaystyle.exe and scheduled task creation named “SlaystyleUpdate”.

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