FORTINET Security Advisory
Published Date: Not specified
Advisory Summary
⬛ ⚠️ Title: JWT authentication bypass risk in FortiMonitorOnSight (FortiMonitorOnSight web GUI)
📌 Summary (what’s happening):
FortiMonitorOnSight contains a vulnerability related to Sensitive Information in Source Code (CWE-540) where a JWT used for authentication in the web GUI is signed with a static key. This can enable a remote, unauthenticated attacker to forge or reuse JWTs to bypass authentication, potentially reaching protected functionality without valid credentials.
- Critical exposure for organizations relying on exposed FortiMonitorOnSight web interfaces
- Authentication bypass (CVSS 9.6) can lead to downstream compromise (data exposure, admin actions, lateral movement depending on what the portal exposes)
- Unauthenticated attack path increases likelihood of automated exploitation if internet-facing
- High priority if assets are reachable externally or from broad internal networks
- Consider whether monitoring/observability components can be leveraged as a staging point into the environment
- Validate whether related Forti components are deployed in “stack” configurations that expand blast radius
🚨 Recommended actions (do now):
1. Check FortiMonitorOnSight exposure: restrict management/portal access via IP allowlists, VPN, or zero-trust access.
2. Apply the PSIRT fix referenced by Fortinet (per affected versions).
3. Rotate/replace any credentials and tokens if the static JWT signing key (or related logic) was leveraged.
4. Review web access logs for suspicious JWT activity and unusual unauthenticated hits to auth-protected endpoints.
5. Harden admin planes: enforce MFA where supported for any remaining auth flows, and segment monitoring interfaces from general networks.
- CWE-540: Sensitive information in source code
- Forged/reused JWT due to static signing key in the web GUI authentication mechanism
- CVSSv3: 9.6 (high confidence severity)
🔗
Reference: Vendor Advisory