{
  "family": "firehooker",
  "sample_count": 1,
  "category": "trojan",
  "description": "<h3>Executive Summary</h3>\nFirehooker is a highly specialized Information Stealer (Info-Stealer) designed specifically to target web browsers, with a historical focus on Mozilla Firefox (hence the name). Its primary objective is to execute a \"man-in-the-browser\" (MitB) attack by hooking into the browser's core API functions, allowing threat actors to intercept, record, and steal sensitive credentials, session tokens, and financial data in real-time as the user types them.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nFirehooker is typically distributed as a secondary payload, dropped onto a system by an initial access broker, a downloader trojan, or via an exploit kit originating from a compromised website.\n\nUpon execution, Firehooker performs advanced, targeted espionage:\n<ul>\n<li><strong>Advanced API Hooking (MitB):</strong> Instead of relying on a simple, noisy global keylogger, Firehooker injects malicious DLLs directly into the active browser process (e.g., `firefox.exe`, `chrome.exe`). It hooks specific cryptographic and network APIs (like `PR_Write` or `HttpSendRequest`). This allows the malware to capture passwords and credit card numbers *before* they are encrypted via HTTPS/SSL.</li>\n<li><strong>Form Grabbing and Web Injects:</strong> Because it sits inside the browser, Firehooker can perform \"form grabbing\"—stealing data submitted in HTML forms. Advanced variants can dynamically inject malicious HTML fields into legitimate banking websites (e.g., asking for an ATM PIN) to steal additional 2FA data.</li>\n<li><strong>Data Exfiltration:</strong> All intercepted data is compiled, encrypted, and exfiltrated via HTTP POST requests to an attacker-controlled command-and-control (C2) server.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nA Firehooker infection is a critical security incident. Because it operates via API hooking within the browser, the data theft is invisible to the user; the padlock icon still shows a secure HTTPS connection. The stolen session tokens and credentials can be immediately used to execute fraudulent financial transactions or access secure corporate portals.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>Global Credential Reset:</strong> ALL credentials entered on the compromised machine while infected—especially banking passwords, corporate VPN logins, and webmail access—must be considered compromised and reset immediately from a *different, clean device*.</li>\n<li><strong>MFA Token Revocation:</strong> Assume session cookies were stolen. Force an immediate sign-out of all active sessions for critical web applications to invalidate the stolen tokens.</li>\n<li><strong>Endpoint Eradication:</strong> The sophisticated process injection techniques used by Firehooker necessitate a full forensic review. Re-imaging the machine from a trusted baseline is required to ensure complete eradication and that no hidden hooks remain in the system.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Trojan.Firehooker",
    "PWS.Firehooker",
    "Banker.Hooker"
  ],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Firehooker and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Firehooker 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 Firehooker establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Firehooker 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 Firehooker compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Firehooker 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 Trojan.Firehooker?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Trojan.Firehooker 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 Trojan.Firehooker across enterprise endpoints?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Defenders should hunt for Trojan.Firehooker 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": [
    "T1185",
    "T1056.001",
    "T1189",
    "T1555.003"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "type": "Information Stealer / Banker",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "mitre_attack_detail": [
    {
      "id": "T1185",
      "name": "Browser Session Hijacking (Ad injection and tracking)",
      "tactic": "Collection"
    },
    {
      "id": "T1056.001",
      "name": "Keylogging",
      "tactic": "Credential Access"
    },
    {
      "id": "T1189",
      "name": "Drive-by Compromise",
      "tactic": "Initial Access"
    },
    {
      "id": "T1555.003",
      "name": "Credentials from Web Browsers",
      "tactic": "Unknown"
    }
  ],
  "containment_steps": [
    "Sever network connectivity for the flagged endpoint to terminate persistent command-and-control (C2) communication channels and stop Firehooker from retrieving secondary stage payloads.",
    "Capture process memory triage to detect and terminate malicious threads injected by Firehooker into legitimate system processes such as explorer.exe or svchost.exe.",
    "Audit Windows Registry Run keys (HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run) and Task Scheduler entries to locate and purge Firehooker persistence hooks.",
    "Deploy updated enterprise EDR detection signatures and conduct an out-of-band endpoint scan to isolate dropped binaries and staged payloads.",
    "Rotate all credentials, domain user passwords, and session cookies active on the system during the Firehooker execution timeframe."
  ],
  "what_to_avoid": [
    "Do not assume the incident is resolved simply because an antivirus tool removed the initial Firehooker dropper; always verify that secondary payloads and persistence hooks have been eradicated.",
    "Avoid logging in with Domain Admin or privileged credentials on a machine suspected of running Firehooker until memory triage is complete.",
    "Do not delay host isolation; automated lateral movement and credential dumping can occur within minutes of initial execution."
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 7"
  ]
}