CVE-2024-46310: Cfx.re FXServer Auth Bypass Vulnerability

CVE-2024-46310 Overview

CVE-2024-46310 is a critical Incorrect Access Control vulnerability affecting Cfx.re FXServer version 9601 and earlier. This security flaw allows unauthenticated users to modify and read arbitrary user data via an exposed API endpoint. The vulnerability stems from improper preservation of permissions (CWE-281), enabling attackers to bypass authorization controls and gain unauthorized access to sensitive information.

FXServer is the server component for FiveM and RedM, popular multiplayer modification frameworks for Grand Theft Auto V and Red Dead Redemption 2. Given the widespread use of these platforms in gaming communities, this vulnerability poses a significant risk to server operators and their user bases.

Critical Impact

Unauthenticated attackers can read and modify arbitrary user data through exposed API endpoints, potentially compromising entire FXServer deployments and affecting all connected users.

Affected Products

• Cfx.re FXServer v9601 and earlier
• FiveM servers running vulnerable FXServer versions
• RedM servers running vulnerable FXServer versions

Discovery Timeline

• 2025-01-13 - CVE-2024-46310 published to NVD
• 2025-01-16 - Last updated in NVD database

Technical Details for CVE-2024-46310

Vulnerability Analysis

This vulnerability represents a fundamental failure in access control implementation within FXServer's API architecture. The exposed API endpoint lacks proper authentication checks, allowing any network-accessible attacker to interact with user data without providing valid credentials. The attack can be executed remotely with low complexity, requiring no user interaction or special privileges.

The impact is severe from both confidentiality and integrity perspectives. Attackers can extract sensitive user information and modify user records at will, potentially leading to account takeovers, data manipulation, and service disruption. The lack of authentication on critical API endpoints represents a significant architectural oversight.

Root Cause

The root cause is classified under CWE-281 (Improper Preservation of Permissions). The FXServer implementation fails to properly enforce access control checks on API endpoints that handle user data operations. This allows the API to process requests from unauthenticated sources as if they were authorized, bypassing the intended permission model entirely.

Attack Vector

The vulnerability is exploitable over the network without requiring authentication. An attacker can target any FXServer instance that has the vulnerable API endpoint exposed. The attack methodology involves:

1. Identifying FXServer instances running version 9601 or earlier
2. Locating the exposed API endpoint handling user data
3. Crafting malicious requests to read or modify user data
4. Executing requests without providing authentication credentials

The network-based attack vector combined with no authentication requirements makes this vulnerability particularly dangerous for internet-facing FXServer deployments.

The vulnerability exists in the API endpoint handling logic where authorization checks should validate the requesting entity before processing user data operations. For detailed technical information and proof-of-concept details, refer to the GitHub CVE-2024-46310 Repository.

Detection Methods for CVE-2024-46310

Indicators of Compromise

• Unusual API requests to user data endpoints from unauthenticated sources
• Unexpected modifications to user records without corresponding administrative actions
• Access logs showing requests to sensitive API endpoints lacking authentication headers
• Anomalous data exfiltration patterns from FXServer instances

Detection Strategies

• Monitor FXServer access logs for unauthenticated requests to API endpoints handling user data
• Implement network traffic analysis to detect unauthorized API interactions
• Deploy Web Application Firewall (WAF) rules to flag requests to sensitive endpoints without valid authentication tokens
• Conduct regular security audits of FXServer configurations and API access patterns

Monitoring Recommendations

• Enable verbose logging on FXServer instances to capture all API interactions
• Set up alerts for bulk data access or modification operations
• Monitor for reconnaissance activity targeting FXServer API endpoints
• Review authentication failures and access patterns periodically

How to Mitigate CVE-2024-46310

Immediate Actions Required

• Upgrade FXServer to a version newer than v9601 that addresses this vulnerability
• Restrict network access to FXServer API endpoints using firewall rules
• Implement additional authentication layers if immediate patching is not possible
• Review and audit user data for signs of unauthorized access or modification

Patch Information

Server administrators should update FXServer to the latest available version from Cfx.re. Verify the installed version and ensure it is newer than v9601. After updating, review API endpoint configurations to confirm proper access controls are in place.

Workarounds

• Deploy a reverse proxy with authentication requirements in front of the FXServer API endpoints
• Use firewall rules to restrict API access to trusted IP addresses only
• Disable or limit access to the affected API endpoints until patching is complete
• Implement network segmentation to isolate FXServer instances from untrusted networks

# Example firewall rule to restrict API access (iptables)
# Replace 30120 with your actual FXServer port and trusted_ip with your admin IP
iptables -A INPUT -p tcp --dport 30120 -s trusted_ip -j ACCEPT
iptables -A INPUT -p tcp --dport 30120 -j DROP