CVE-2024-38513: Gofiber Fiber Auth Bypass Vulnerability

CVE-2024-38513 Overview

CVE-2024-38513 is a session fixation vulnerability in GoFiber, an Express-inspired web framework written in Go. This vulnerability exists in the session middleware of GoFiber versions prior to 2.52.5 and allows attackers to supply their own session_id value, resulting in the creation of a session with that attacker-controlled key. If a web application relies on the mere presence of a session for security purposes, this flaw can lead to unauthorized access and session fixation attacks.

Critical Impact

Attackers can hijack user sessions by forcing users to use a predetermined session ID, potentially leading to complete account takeover, unauthorized access to sensitive data, and full application compromise.

Affected Products

• GoFiber Fiber versions prior to 2.52.5
• GoFiber session middleware in versions 2.x through 2.52.4
• Applications using GoFiber's session middleware for authentication or authorization

Discovery Timeline

• 2024-07-01 - CVE-2024-38513 published to NVD
• 2025-10-02 - Last updated in NVD database

Technical Details for CVE-2024-38513

Vulnerability Analysis

This session fixation vulnerability (CWE-384) occurs due to improper session ID validation in GoFiber's session middleware. The core issue is that the middleware accepts user-supplied session identifiers without verification, allowing an attacker to pre-set or inject a known session ID. When the victim subsequently authenticates, the application associates their authenticated session with the attacker's predetermined session ID, giving the attacker access to the victim's authenticated session.

The vulnerability is particularly dangerous because it can be exploited remotely over the network without requiring any authentication or user interaction. An attacker can craft a malicious URL containing a predetermined session ID and trick a victim into clicking it. Once the victim authenticates, the attacker can use the same session ID to access the victim's account.

Root Cause

The root cause of this vulnerability lies in the session middleware's failure to properly validate and regenerate session identifiers. Specifically, the middleware allows client-supplied session IDs to be used directly for session creation without verifying that the session ID was generated server-side. Secure session management requires that session identifiers be cryptographically generated by the server and that session IDs be regenerated upon authentication state changes.

Attack Vector

The attack vector for CVE-2024-38513 follows the classic session fixation pattern:

1. Session ID Injection: The attacker crafts a request containing a predetermined session ID and sends it to the target application. The application's session middleware accepts this ID and creates a session with that key.

2. Victim Luring: The attacker tricks the victim into visiting the application using the predetermined session ID, typically through a malicious link or embedded content.

3. Session Hijacking: Once the victim authenticates through the application, their authenticated session becomes associated with the attacker's known session ID. The attacker can then use this session ID to impersonate the victim and gain unauthorized access.

This vulnerability is exploitable over the network and requires no privileges or special access to execute. For technical details on the vulnerability and the fix, see the GitHub Security Advisory GHSA-98j2-3j3p-fw2v.

Detection Methods for CVE-2024-38513

Indicators of Compromise

• Multiple requests from different IP addresses using identical session IDs
• Session IDs appearing in URL parameters or referrer logs
• Unusual session activity patterns where a session is created before authentication occurs
• Sessions that persist across multiple IP addresses or user agents

Detection Strategies

• Monitor application logs for session IDs being passed in URL parameters or request bodies
• Implement alerting for sessions that change IP addresses or user agents after authentication
• Review access logs for patterns of session ID reuse across different client fingerprints
• Audit GoFiber application dependencies to identify vulnerable versions using go list -m all | grep fiber

Monitoring Recommendations

• Enable detailed session logging to track session creation, authentication events, and session usage patterns
• Implement rate limiting on session creation endpoints to detect brute-force session injection attempts
• Deploy web application firewalls (WAF) with rules to detect session fixation patterns
• Set up alerts for anomalous session behavior, such as pre-authentication session access patterns

How to Mitigate CVE-2024-38513

Immediate Actions Required

• Upgrade GoFiber to version 2.52.5 or higher immediately
• Audit current sessions and invalidate any suspicious sessions that may have been compromised
• Review application code to ensure session-based security controls are not solely relying on session presence
• Implement session ID regeneration after successful authentication as a defense-in-depth measure

Patch Information

The vulnerability has been addressed in GoFiber version 2.52.5. The fix ensures that session IDs are securely generated by the server and not accepted from user input. Users should upgrade by updating their go.mod file to require github.com/gofiber/fiber/v2 version 2.52.5 or higher. The specific commit addressing this issue is available at GitHub Commit 66a8814.

Workarounds

• Implement additional server-side validation to ensure session IDs are not supplied by users and are securely generated by the server
• Enforce session ID regeneration upon authentication to invalidate any pre-set session IDs
• Implement strict session expiration policies with short session lifetimes
• Add IP address and user agent binding to sessions to detect session migration attempts

# Update GoFiber to patched version
go get github.com/gofiber/fiber/v2@v2.52.5
go mod tidy