{
  "family": "orcus",
  "sample_count": 66,
  "category": "trojan",
  "description": "Backdoor:Win32/Orcus is a highly advanced, feature-rich Remote Access Trojan (RAT) that was controversially marketed and sold commercially as a legitimate 'Remote Administration Tool' before its author was prosecuted. It is heavily utilized by cybercriminals for espionage, credential theft, and system disruption.<br><br><b>Understanding Orcus RAT</b><br>To the end-user, an Orcus infection is entirely invisible. For incident responders, Orcus is a top-tier threat. Because it was developed and sold commercially (often for around $40), it features a highly polished, modular architecture. Attackers can extend its capabilities using custom plugins written in C# or VB.NET. Its capabilities are vast: a fully interactive remote shell, keylogging, webcam/microphone capture, password extraction from browsers, and even the ability to trigger a devastating Blue Screen of Death (BSOD).<br><br><b>Execution and Evasion Strategies</b><br>Orcus is typically delivered via spearphishing (weaponized attachments) or drive-by downloads. Upon execution, the payload establishes deep persistence, frequently modifying the Registry Run keys (`HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run`) or creating hidden scheduled tasks. Orcus is adept at evasion; it actively attempts to detect virtual machines or sandboxes, terminating execution if analysis tools are found. It communicates with its C2 server using a proprietary, encrypted TCP protocol, often disguised to look like legitimate HTTP or HTTPS traffic. It frequently injects its core DLL into legitimate processes like `explorer.exe` or `svchost.exe`.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is total endpoint compromise, massive data exfiltration, and severe privacy violations. EDR platforms will trigger on Orcus's process injection attempts and its aggressive harvesting of browser credential databases. Network logs will show sustained, encrypted TCP connections. Threat hunters should look for the presence of the default Orcus mutexes or its heavily obfuscated configuration files stored in the `%AppData%` directory.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1071.001",
    "T1055.001",
    "T1056.001",
    "T1125",
    "T1497.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1055.001",
      "name": "Process Injection: Dynamic-link Library Injection",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1056.001",
      "name": "Input Capture: Keylogging",
      "tactic": "Collection"
    },
    {
      "id": "T1125",
      "name": "Video/Audio Capture",
      "tactic": "Collection"
    },
    {
      "id": "T1071.001",
      "name": "Application Layer Protocol: Web Protocols",
      "tactic": "Command and Control"
    },
    {
      "id": "T1497.001",
      "name": "Virtualization/Sandbox Evasion: System Checks",
      "tactic": "Defense Evasion"
    }
  ],
  "containment_steps": [
    "Immediately sever the endpoint from the network to terminate the active Orcus session, halting data exfiltration and preventing the attacker from triggering a BSOD.",
    "Do NOT reboot the machine immediately; capture a forensic memory image to extract the active Orcus configuration and C2 details.",
    "Force a global password reset for all accounts accessed by the user, as Orcus aggressively targets saved browser and email credentials.",
    "Assume the machine is fully compromised; perform a clean operating system rebuild to ensure complete eradication."
  ],
  "what_to_avoid": [
    "Do not leave the machine connected to the network during triage; the attacker has live access and can manually destroy evidence.",
    "Avoid relying solely on file deletion; Orcus often runs in memory and will recreate deleted files if the injected process is not killed."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}