Introduction
With crafted cookies, attackers can force administrative logouts or escalate privileges in FortiIsolator deployments. Either outcome hits security operations and policy control directly. Organizations that rely on FortiIsolator for browser isolation and threat prevention must address this vulnerability to prevent disruption or unauthorized configuration changes.
Fortinet is a leading global cybersecurity vendor whose products include FortiGate firewalls, FortiMail, and FortiIsolator. FortiIsolator protects users from web-based threats by running web content in remote containers. Enterprises use it widely to reduce zero-day and phishing risk, so flaws in its authentication mechanisms matter more than usual for operational security.
Technical Information
CVE-2024-33507 combines two flaws in FortiIsolator's authentication mechanism: insufficient session expiration (CWE-613) and incorrect authorization (CWE-863). Both are present in these versions:
- 2.4.0 through 2.4.4
- All 2.3 releases
- 2.2.0
- All 2.1 releases
- All 2.0 releases
Mechanism:
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Insufficient Session Expiration (CWE-613): Session management does not properly expire or validate session state. An unauthenticated remote attacker can send a crafted cookie to the authentication endpoint and deauthenticate active admin sessions. Administrators are logged out and denied access.
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Incorrect Authorization (CWE-863): The authorization mechanism trusts permission indicators in client-supplied cookies. An authenticated user with read-only access can edit their cookie to gain write access and get past the intended server-side permission checks. From there, they can make unauthorized configuration changes and modify policies.
No public code snippets or vulnerable code fragments are available. The root cause is that FortiIsolator relies on client-side cookie data for both session validity and authorization, without enough server-side validation or cryptographic integrity checks.
Affected Systems and Versions
- FortiIsolator 2.4.0 through 2.4.4
- All FortiIsolator 2.3 versions
- FortiIsolator 2.2.0
- All FortiIsolator 2.1 versions
- All FortiIsolator 2.0 versions
FortiIsolator 3.0 and later are not affected.
Vendor Security History
Fortinet has a history of authentication and session management vulnerabilities across its products. It also publishes advisories regularly and runs a mature PSIRT process. Earlier issues include session expiration flaws in FortiSandbox and authentication bypasses in FortiOS and FortiProxy. Fortinet generally patches promptly, and its advisories are detailed. CVE-2024-33507 was discovered internally, which points to proactive security practices.
