CVE-2024-6593: WatchGuard Authentication Gateway Auth Bypass

CVE-2024-6593 Overview

An Incorrect Authorization vulnerability (CWE-863) exists in WatchGuard Authentication Gateway, also known as the Single Sign-On (SSO) Agent, running on Windows. This security flaw allows an attacker with network access to execute restricted management commands without proper authorization checks. The vulnerability affects all versions of the Authentication Gateway through version 12.10.2.

Critical Impact

Unauthenticated attackers with network access can bypass authorization controls and execute restricted management commands, potentially compromising the integrity and confidentiality of the authentication gateway infrastructure.

Affected Products

• WatchGuard Authentication Gateway (Single Sign-On Agent) through version 12.10.2
• Windows-based deployments of WatchGuard SSO Agent
• Enterprise environments utilizing WatchGuard Single Sign-On functionality

Discovery Timeline

• 2024-09-25 - CVE-2024-6593 published to NVD
• 2024-10-01 - Last updated in NVD database

Technical Details for CVE-2024-6593

Vulnerability Analysis

This vulnerability stems from improper authorization controls within the WatchGuard Authentication Gateway service. The Authentication Gateway serves as a critical component in WatchGuard's Single Sign-On infrastructure, facilitating centralized authentication across enterprise environments. Due to the incorrect authorization implementation, the service fails to properly validate that incoming requests to execute management commands originate from authorized sources.

The vulnerability enables network-accessible exploitation, meaning any attacker who can reach the service over the network can potentially abuse this flaw. The attack complexity is low and requires no privileges or user interaction, making it particularly dangerous in enterprise environments where the Authentication Gateway is accessible on the network.

Successful exploitation can result in high impact to both confidentiality and integrity of the affected system. Attackers could potentially access sensitive authentication data, modify configuration settings, or manipulate the SSO infrastructure to their advantage.

Root Cause

The root cause of CVE-2024-6593 is an incorrect authorization vulnerability (CWE-863). The WatchGuard Authentication Gateway fails to properly verify that requests to execute management commands are coming from authorized administrative sources. This missing or inadequate authorization check allows unauthorized parties to invoke privileged functionality that should be restricted to authenticated administrators only.

Attack Vector

The attack vector is network-based, allowing remote exploitation. An attacker positioned on the same network as the vulnerable Authentication Gateway—or with network access to it—can send crafted requests to execute restricted management commands. The vulnerability does not require authentication, meaning attackers can exploit it without valid credentials.

The exploitation methodology involves sending management commands directly to the Authentication Gateway service. Without proper authorization validation, the service processes these commands as if they originated from a legitimate administrator. This could enable attackers to enumerate users, modify authentication policies, extract sensitive information, or disrupt SSO functionality across the enterprise.

For detailed technical information and exploitation specifics, refer to the WatchGuard Security Advisory WGSA-2024-00015.

Detection Methods for CVE-2024-6593

Indicators of Compromise

• Unexpected or unauthorized management command executions logged by the Authentication Gateway
• Unusual network connections to the Authentication Gateway service from non-administrative sources
• Configuration changes to SSO policies without corresponding administrator activity
• Anomalous authentication behavior or SSO disruptions across the enterprise

Detection Strategies

• Monitor Authentication Gateway logs for management command executions from unexpected source IP addresses
• Implement network segmentation monitoring to detect unauthorized access attempts to the SSO Agent
• Deploy intrusion detection rules to identify patterns of management command abuse
• Correlate Authentication Gateway activity with administrator login records to identify unauthorized actions

Monitoring Recommendations

• Enable verbose logging on the WatchGuard Authentication Gateway to capture all management operations
• Configure SIEM alerts for management commands originating from non-approved IP addresses or subnets
• Monitor network traffic to and from the Authentication Gateway service for anomalous patterns
• Regularly audit Authentication Gateway configurations for unauthorized modifications

How to Mitigate CVE-2024-6593

Immediate Actions Required

• Upgrade WatchGuard Authentication Gateway to a patched version as specified in the vendor advisory
• Restrict network access to the Authentication Gateway management interface to authorized administrative networks only
• Implement firewall rules to limit which hosts can communicate with the SSO Agent service
• Review Authentication Gateway logs for any evidence of exploitation

Patch Information

WatchGuard has addressed this vulnerability in versions subsequent to 12.10.2. Organizations should consult the WatchGuard Security Advisory WGSA-2024-00015 for specific patching guidance and download links. Apply the security update as soon as possible to remediate this critical vulnerability.

Workarounds

• Implement strict network segmentation to isolate the Authentication Gateway from untrusted network segments
• Configure host-based firewalls on the Windows server running the SSO Agent to restrict management access
• Deploy network ACLs to ensure only authorized administrative workstations can reach the Authentication Gateway
• Consider temporarily disabling network access to the management interface until patching can be completed

# Windows Firewall configuration example to restrict access to SSO Agent
# Restrict access to the Authentication Gateway to specific admin subnet
netsh advfirewall firewall add rule name="Block SSO Agent - All" dir=in action=block protocol=tcp localport=4116
netsh advfirewall firewall add rule name="Allow SSO Agent - Admin Subnet" dir=in action=allow protocol=tcp localport=4116 remoteip=10.0.1.0/24