CVE-2024-6592: WatchGuard Authentication Gateway Bypass

CVE-2024-6592 Overview

CVE-2024-6592 is an Incorrect Authorization vulnerability affecting the protocol communication between the WatchGuard Authentication Gateway (also known as Single Sign-On Agent) on Windows and the WatchGuard Single Sign-On Client on Windows and MacOS. This authentication bypass vulnerability allows attackers to circumvent authorization controls in the SSO communication protocol, potentially gaining unauthorized access to protected resources.

Critical Impact

This vulnerability enables authentication bypass through improper authorization checks in the SSO protocol, allowing attackers to impersonate authenticated users and gain unauthorized access to enterprise resources protected by WatchGuard SSO solutions.

Affected Products

• WatchGuard Authentication Gateway (SSO Agent) through version 12.10.2
• WatchGuard Single Sign-On Client for Windows through version 12.7
• WatchGuard Single Sign-On Client for MacOS through version 12.5.4

Discovery Timeline

• 2024-09-25 - CVE-2024-6592 published to NVD
• 2025-10-15 - Last updated in NVD database

Technical Details for CVE-2024-6592

Vulnerability Analysis

This vulnerability stems from incorrect authorization handling (CWE-863) combined with missing authentication for critical functions (CWE-306) in the communication protocol between WatchGuard's Authentication Gateway and the Single Sign-On Client. The flaw exists in how the SSO components validate and authorize protocol messages during the authentication handshake process.

When the Authentication Gateway receives requests from SSO Clients, it fails to properly verify the authorization status of the requesting entity. This allows an attacker with network access to craft malicious protocol messages that bypass the authentication requirements, effectively impersonating legitimate users or clients without providing valid credentials.

The network-accessible nature of this vulnerability means that any attacker who can reach the Authentication Gateway over the network can potentially exploit this flaw without requiring any prior authentication or user interaction.

Root Cause

The root cause of CVE-2024-6592 lies in the improper implementation of authorization checks within the SSO protocol communication layer. Specifically, the Authentication Gateway does not adequately validate the identity and authorization level of incoming connections before processing authentication-related requests. This missing authentication for critical functions (CWE-306) combined with incorrect authorization logic (CWE-863) creates a condition where unauthorized parties can successfully complete authentication workflows.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no authentication or user interaction. An attacker positioned on the same network as the WatchGuard Authentication Gateway can exploit this vulnerability by:

1. Identifying network endpoints where the WatchGuard Authentication Gateway is listening for SSO Client connections
2. Crafting protocol messages that exploit the incorrect authorization logic
3. Sending these malicious messages to bypass authentication checks
4. Gaining unauthorized access as if they were a legitimately authenticated user

The vulnerability affects the communication protocol itself, meaning the attack can be conducted remotely against any exposed Authentication Gateway service. Organizations with internet-facing or broadly accessible SSO infrastructure are at heightened risk.

Detection Methods for CVE-2024-6592

Indicators of Compromise

• Unexpected authentication events from unrecognized client IP addresses or hosts in WatchGuard Authentication Gateway logs
• Anomalous SSO protocol traffic patterns indicating crafted or malformed authentication requests
• Authentication success events without corresponding valid user credential submissions
• Unusual access to protected resources by users who should not have authenticated during that timeframe

Detection Strategies

• Monitor WatchGuard Authentication Gateway logs for authentication bypass attempts or anomalous successful authentications
• Implement network traffic analysis to detect unusual SSO protocol communication patterns
• Deploy intrusion detection rules to identify malformed or suspicious SSO protocol messages
• Correlate authentication events across multiple systems to identify discrepancies indicating bypass attempts

Monitoring Recommendations

• Enable detailed logging on all WatchGuard Authentication Gateway instances and centralize log collection
• Configure alerts for authentication events from unexpected source IP ranges or during unusual hours
• Implement baseline analysis for normal SSO traffic patterns to detect deviations
• Review access logs for protected resources to identify unauthorized access that may indicate successful exploitation

How to Mitigate CVE-2024-6592

Immediate Actions Required

• Update WatchGuard Authentication Gateway to a version newer than 12.10.2
• Update WatchGuard Single Sign-On Client for Windows to a version newer than 12.7
• Update WatchGuard Single Sign-On Client for MacOS to a version newer than 12.5.4
• Restrict network access to the Authentication Gateway service to only trusted client IP ranges

Patch Information

WatchGuard has released security updates to address this vulnerability. Organizations should consult the WatchGuard Security Advisory WGSA-2024-00014 for specific version information and download links for patched software. It is critical to update all affected components including both the Authentication Gateway and all deployed SSO Clients across Windows and MacOS platforms.

Workarounds

• Implement network segmentation to restrict access to the Authentication Gateway from untrusted networks
• Deploy firewall rules to limit SSO protocol communication to known, legitimate client IP addresses only
• Enable additional authentication layers or multi-factor authentication where possible to reduce impact of potential bypass
• Consider temporarily disabling SSO functionality in high-security environments until patches can be applied

# Example firewall configuration to restrict Authentication Gateway access
# Limit SSO Agent communication to specific trusted subnets
# Windows Firewall (PowerShell)
New-NetFirewallRule -DisplayName "Restrict SSO Agent" -Direction Inbound -Protocol TCP -LocalPort 4116 -RemoteAddress 10.0.0.0/8,172.16.0.0/12,192.168.0.0/16 -Action Allow
New-NetFirewallRule -DisplayName "Block SSO Agent External" -Direction Inbound -Protocol TCP -LocalPort 4116 -Action Block