Play Ransomware Encryption: How It Works

Summary

Play, also known as PlayCrypt, is a prolific ransomware group that uses a closed operational model to conduct double-extortion attacks. The group typically exfiltrates sensitive data before deploying encryptors and demanding ransom payments. Its campaigns frequently target critical infrastructure and healthcare organizations across North America, South America, and Europe.

Investigation

Forensic analysis of a recent incident showed initial access through a compromised SonicWall VPN, followed by deployment of SystemBC for C2. The attackers abused the victim’s own SentinelOne uninstallation utility to disable EDR and distributed tools such as PsExec through the SYSVOL share. Data staging was also observed in the low-traffic C:\PerfLogs directory using WinRAR and WinSCP.

Mitigation

Organizations should enable vendor-authenticated tamper protection to prevent unauthorized removal of EDR tools. Multi-factor authentication should be enforced across all VPN services to reduce the risk of initial access through remote infrastructure. Monitoring for high-volume SFTP activity or unusual WinSCP transfers can also help detect attempted data exfiltration.

Response

If Play ransomware activity is suspected, organizations should immediately activate incident response procedures covering both data breach containment and encryption recovery. Windows Event ID 1102, which indicates event log clearing, should be treated as a high-confidence sign of imminent encryption. Responders should also investigate unauthorized executables in C:\PerfLogs and SystemBC DLLs stored in the Windows Tasks directory.

Simulation Execution

Prerequisite: The Telemetry & Baseline Pre-flight Check must have passed.

Rationale: This section details the precise execution of the adversary technique (TTP) designed to trigger the detection rule. The commands and narrative MUST directly reflect the TTPs identified and aim to generate the exact telemetry expected by the detection logic. Abstract or unrelated examples will lead to misdiagnosis.

• Attack Narrative & Commands: The adversary has successfully compromised a workstation and is preparing to deploy ransomware (T1486). To prevent the SOC from investigating the initial entry and lateral movement, the attacker decides to wipe the forensic trail. The attacker executes a command using wevtutil.exe, a native Windows utility, to clear the Security event log. This action is a classic anti-forensic technique intended to hide the presence of unauthorized tools and account usage.

• Regression Test Script:

  # Simulation Script: Clear Security Event Log to trigger Event ID 1102
  # Note: This must be run in an Elevated (Administrator) PowerShell session.
  
  Write-Host "[!] Starting Simulation: Clearing Security Event Log..." -ForegroundColor Yellow
  
  try {
      # Using wevtutil to clear the Security channel
      wevtutil cl Security
  
      if ($LASTEXITCODE -eq 0) {
          Write-Host "[+] Success: Security log cleared. Check SIEM for Event ID 1102." -ForegroundColor Green
      } else {
          Write-Host "[-] Failure: Could not clear log. Ensure you are running as Administrator." -ForegroundColor Red
      }
  } catch {
      Write-Host "[-] Error: $($_.Exception.Message)" -ForegroundColor Red
  }

• Cleanup Commands:

  # Cleanup: Note that once the log is cleared, it cannot be 'un-cleared'. 
  # This command simply ensures we acknowledge the state.
  Write-Host "[*] Cleanup: Simulation complete. The Security Log is now empty. Manual log rotation or system reboot may be required to restore baseline logging levels." -ForegroundColor Cyan