Remediation/Mitigation Strategy for CVE-2025-1293 - Hermes JWT Validation Vulnerability

This document outlines the remediation and mitigation strategy for CVE-2025-1293, a vulnerability affecting Hermes versions up to 0.4.0.

1. Vulnerability Description:

  • Vulnerability: Improper JWT Validation in AWS ALB Authentication Mode
  • Description: Hermes versions up to 0.4.0 do not properly validate the JSON Web Token (JWT) provided when using the AWS Application Load Balancer (ALB) authentication mode. This allows for the possibility of crafting or manipulating JWTs to bypass authentication. An attacker could potentially gain unauthorized access to systems or resources protected by Hermes.
  • Affected Versions: Hermes versions up to 0.4.0.
  • Fixed Version: Hermes 0.5.0.

2. Severity Assessment:

Based on the provided data:

  • CVSS v3 Score: 8.2 (High)
  • CVSS Vector: The provided data lacks the complete CVSS vector string. A CVSS vector typically looks like: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N (This is an example. The correct vector for CVE-2025-1293 would need to be obtained from the NVD or a similar vulnerability database).
  • Impact:
    • Confidentiality: High - Unauthorized access to sensitive data.
    • Integrity: High - Potential to modify or corrupt data.
    • Availability: Low - While the CVSS score doesn’t directly indicate impact on availability, successful exploitation could lead to service disruptions.
  • Severity: High

3. Known Exploit Information:

The provided data doesn’t explicitly confirm a public exploit, only that it “potentially” allows for authentication bypass. However, given the nature of JWT validation vulnerabilities, it is likely that proof-of-concept exploits or exploit code could be developed by security researchers or malicious actors if the vulnerability is publicly known. Assume that an exploit could be created.

4. Remediation Strategy:

  • Immediate Action: Upgrade Hermes to Version 0.5.0 or Later: This is the primary and most effective remediation. All instances of Hermes running versions 0.4.0 or earlier must be upgraded immediately.
    • Testing: Before deploying to production, thoroughly test the upgraded version in a non-production environment to ensure compatibility and stability with your existing infrastructure and applications.
    • Rollback Plan: Develop a rollback plan in case the upgrade introduces unforeseen issues. This should include a mechanism to quickly revert to the previous, vulnerable version if necessary. However, prioritize security and quickly re-attempt the upgrade once issues are resolved.

5. Mitigation Strategies (While Upgrading / In Case Upgrade is Immediately Impossible):

If an immediate upgrade is not possible due to operational constraints, consider these temporary mitigation strategies:

  • Web Application Firewall (WAF) Rules:
    • Implement WAF rules to inspect and block requests with suspicious or malformed JWTs. This requires a deep understanding of JWT structure and common attack vectors. This is a complex mitigation and may lead to false positives and false negatives.
    • Rate limit requests to Hermes endpoints to reduce the impact of potential brute-force attacks aimed at exploiting the vulnerability.
  • Network Segmentation:
    • Isolate Hermes instances behind a secure network segment with strict access control policies. Limit access to Hermes only to authorized users and systems.
  • Monitor and Alert:
    • Implement robust monitoring and alerting for any suspicious activity related to Hermes, such as:
      • Unusual authentication attempts.
      • Unexpected error codes.
      • Increased network traffic to Hermes endpoints.
    • Configure logging to capture detailed information about authentication requests and JWT validation attempts.

Important Considerations:

  • Prioritize the Upgrade: Mitigation strategies are only temporary measures. The upgrade to version 0.5.0 or later is the only permanent solution to address the underlying vulnerability.
  • Assume Exploitation: Even if there are no known public exploits, assume that the vulnerability could be exploited and prioritize remediation accordingly.
  • Regular Security Audits: Conduct regular security audits and penetration testing of your systems and applications to identify and address potential vulnerabilities.
  • Stay Informed: Subscribe to security advisories from HashiCorp and other relevant sources to stay informed about new vulnerabilities and security updates.

6. Communication Plan:

  • Communicate the vulnerability and remediation plan to all relevant stakeholders, including:
    • Security teams
    • Operations teams
    • Development teams
    • Application owners

7. Post-Remediation Steps:

  • Validate the Fix: After upgrading to Hermes 0.5.0 or later, verify that the JWT validation issue is resolved. This may involve running penetration tests or vulnerability scans.
  • Review and Update Security Policies: Review and update your security policies and procedures to reflect the lessons learned from this incident.
  • Continuous Monitoring: Continue to monitor Hermes for any signs of suspicious activity.
  • Patch Management: Ensure a robust patch management process is in place to keep all systems up to date with the latest security patches.