9.6
Critical CVE Analysis CISA KEV Active Zero-Day TLP:CLEAR

CVE-2024-55591

FortiOS Authentication Bypass via Node.js WebSocket

Critical authentication bypass vulnerability in Fortinet FortiOS and FortiProxy. Remote unauthenticated attackers can gain super-admin privileges via the Node.js WebSocket module. Actively exploited as a zero-day since November 2024.

CVSS Score
9.6 Critical
Affected Product
Fortinet FortiOS/FortiProxy
CWE
CWE-288
Vendor Advisory
FG-IR-24-535
CISA KEV Date
January 17, 2025

Active Threat Actor Exploitation

This vulnerability is being actively exploited by:

1
Executive Summary
Active Zero-Day Exploitation
CVE-2024-55591 has been actively exploited since mid-November 2024, weeks before public disclosure. Threat actors are gaining super-admin privileges on FortiGate firewalls, creating rogue accounts, and using SSL VPN to tunnel into enterprise networks.

CVE-2024-55591 is an authentication bypass vulnerability in Fortinet FortiOS and FortiProxy. A remote, unauthenticated attacker can send specially crafted requests to the Node.js websocket module to gain super-admin privileges on vulnerable devices.

Key Facts

  • CVSS Score: 9.6 (Critical)
  • Attack Vector: Network (Remote, No Authentication)
  • Active zero-day exploitation since November 2024
  • CISA KEV catalog addition: January 17, 2025
  • Used by Qilin ransomware affiliates for initial access
2
Affected Products

Vulnerable Versions

Product Vulnerable Versions Fixed Version
FortiOS 7.0.0 through 7.0.16 7.0.17 or above
FortiProxy 7.0.0 through 7.0.19 7.0.20 or above
FortiProxy 7.2.0 through 7.2.12 7.2.13 or above

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Detect CVE-2024-55591 Exploitation in Real-Time

BRACE identifies exploitation attempts for this vulnerability and alerts your team immediately:

  • Suspicious jsconsole login activity detection
  • Rogue admin account creation alerts
  • SSL VPN anomaly detection
  • FortiGate configuration change monitoring

Stay Ahead of CVE-2024-55591 Exploitation

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