{
  "family": "flymux",
  "sample_count": 1,
  "category": "advanced_threat",
  "description": "<h3>Executive Summary</h3>\nFlymux is a targeted Information Stealer (Info-Stealer) primarily focused on extracting credentials, session tokens, and stored web browser passwords from compromised Windows systems. It operates as a fast, \"smash-and-grab\" utility favored by cybercriminals for rapid credential harvesting and subsequent server or account compromise.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nFlymux is typically distributed via malicious email attachments (often masquerading as invoices or shipping documents) or bundled within cracked software available on untrustworthy software portals.\n\nUpon execution, Flymux initiates a rapid, localized search for high-value credentials:\n<ul>\n<li><strong>Browser and Email Harvesting:</strong> The malware actively scans the registry and local AppData folders to extract saved passwords, autofill data, and session cookies from major web browsers (Chrome, Firefox, Internet Explorer). It also targets email clients (Outlook, Thunderbird).</li>\n<li><strong>FTP/Webmaster Targeting:</strong> Flymux frequently hunts for configuration files and saved passwords associated with popular FTP clients (like FileZilla or WinSCP). Stolen FTP credentials allow the attacker to deface websites or host further malware payloads.</li>\n<li><strong>Data Exfiltration:</strong> Once the data is harvested, Flymux encrypts the stolen information and transmits it to an attacker-controlled server via HTTP POST requests, completing its execution quickly to evade prolonged detection.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nA Flymux infection poses a severe risk to an organization's internal and external infrastructure. The theft of session cookies can bypass Multi-Factor Authentication (MFA), allowing attackers immediate access to corporate web applications (like O365 or Google Workspace).\n\n<h3>Incident Response and Remediation</h3>\n<ul>\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>Local Password Reset:</strong> All user credentials saved in the affected endpoint's web browsers, email clients, and FTP software must be considered compromised and reset from a clean device.</li>\n<li><strong>Endpoint Eradication:</strong> The malware itself is typically not heavily obfuscated and can often be removed by a reputable EDR or enterprise antivirus solution. Ensure a full system scan is completed to verify eradication.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Trojan.Flymux",
    "PWS.Flymux",
    "TrojanSpy.Flymux"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1555.003",
    "T1539",
    "T1056.001",
    "T1048"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-02T06:48:21Z",
  "type": "Information Stealer",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}