{
  "family": "ircbrute",
  "sample_count": 2,
  "category": "trojan",
  "description": "Trojan:Win32/Ircbrute is a classification for a botnet agent or worm that combines the command-and-control (C2) infrastructure of an Internet Relay Chat (IRC) botnet with aggressive network brute-forcing capabilities. Once it infects a host, it connects to an attacker-controlled IRC channel to receive commands and simultaneously begins scanning the internet or local network to brute-force weak credentials on exposed services (like SSH, RDP, or SQL databases) to spread the infection further (`T1110.001`).<br><br><b>Understanding Ircbrute</b><br>To an end-user, an Ircbrute infection might manifest as slow network performance due to the aggressive scanning. For a network administrator, it represents a significant, 'loud' threat. The infected machine becomes an active attacker, generating massive amounts of outbound traffic as it attempts to compromise other systems, potentially leading to the organization's IP address being blacklisted by external security services.<br><br><b>Execution and Propagation Mechanics</b><br>Upon execution, Ircbrute establishes persistence (usually via Registry Run keys) and initiates an outbound TCP connection to a hardcoded IRC server (often on port 6667 or alternative ports to evade simple firewall rules). Once joined to the C2 channel (`T1071.001`), the bot receives a list of target IP ranges and a dictionary of common usernames and passwords. The malware then executes multi-threaded brute-force attacks (`T1110.001`) against services like SMB (TCP 445), RDP (TCP 3389), or MSSQL (TCP 1433). Upon a successful login, it uses tools like PsExec or WMI to copy itself to the new victim and execute, expanding the botnet.<br><br><b>Indicators of Compromise & Impact</b><br>The primary impact is network congestion, participation in a botnet, and the compromise of other internal servers. Network IoCs are glaring: persistent outbound TCP connections to external IRC servers, coupled with massive spikes in outbound scanning and login attempts (Failed Login Events - Event ID 4625) targeting internal or external infrastructure. Host IoCs include the malware executable (often hidden in `%SystemRoot%` or `%Temp%`) and corresponding persistence mechanisms.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Ircbrute and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Ircbrute is classified as a Trojan. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments."
      }
    },
    {
      "@type": "Question",
      "name": "How does Ircbrute establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Ircbrute typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks."
      }
    },
    {
      "@type": "Question",
      "name": "What are the essential incident response steps for mitigating a Ircbrute compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Ircbrute should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups."
      }
    },
    {
      "@type": "Question",
      "name": "What secondary payloads and staging behaviors are commonly associated with Ircbrute?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Ircbrute frequently operates as a loader or dropper designed to establish a foothold before downloading and executing secondary high-impact malware payloads. Depending on the threat actor's objectives, these dropped modules can range from ransomware and banking injects to modular infostealers and remote management backdoors."
      }
    },
    {
      "@type": "Question",
      "name": "How can security operations teams effectively detect and hunt for Ircbrute across enterprise endpoints?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Defenders should hunt for Ircbrute by deploying behavioral endpoint detection and response (EDR) rules that monitor suspicious process spawning (such as cmd.exe or powershell.exe spawned from office documents or temporary directories), anomalous outbound network connections from non-browser binaries, and unauthorized modifications to Windows Run keys and scheduled task registries."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1547.001",
    "T1046",
    "T1110.001",
    "T1071.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1110.001",
      "name": "Brute Force: Password Guessing (The primary propagation and attack mechanism)",
      "tactic": "Credential Access"
    },
    {
      "id": "T1071.001",
      "name": "Application Layer Protocol: Web Protocols (Using IRC for Command and Control)",
      "tactic": "Command and Control"
    },
    {
      "id": "T1046",
      "name": "Network Service Discovery (Scanning the network for vulnerable services)",
      "tactic": "Discovery"
    },
    {
      "id": "T1547.001",
      "name": "Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder",
      "tactic": "Persistence"
    }
  ],
  "containment_steps": [
    "Segment the infected host immediately to stop the outbound brute-force attacks and prevent lateral movement.",
    "Block outbound IRC traffic (TCP port 6667, 6660-6669) at the perimeter firewall to sever the C2 connection.",
    "Review Active Directory logs for Event ID 4625 (Failed Logon) to identify which accounts were targeted by the brute-force attack and reset compromised passwords.",
    "Enforce strict password complexity and multi-factor authentication (MFA) on all externally facing services (RDP, VPN) to mitigate brute-forcing."
  ],
  "what_to_avoid": [
    "Do not ignore the infection as a simple 'adware' issue; an active Ircbrute infection means your network is being used to attack others.",
    "Avoid cleaning the host without investigating network logs; you must identify if the brute-force attack successfully compromised other internal machines."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 7"
  ]
}