CVE-2021-3311

An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.

An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.

### Impact When logging out, the session ID was not invalidated. This is not a problem while the user is logged out, but as soon as the user logs back in the old session ID would be valid again; which means that anyone that gained access to the old session cookie would be able to act as the logged in user. This is not a major concern for the majority of cases, since it requires a malicious party gaining access to the session cookie in the first place, but nevertheless has been fixed. ### Patches Issue has been patched in Build 472 (v1.0.472) and v1.1.2. ### Workarounds Apply https://github.com/octobercms/library/commit/642f597489e6f644d4bd9a0c267e864cabead024 to your installation manually if unable to upgrade to Build 472 or v1.1.2. ### References - Reported by Anisio (Brazilian Information Security Analyst) - http://cve.circl.lu/cve/CVE-2021-3311 ### For more information If you have any questions or comments about this advisory: * Email us at [hello@octobercms.com](mailto:hello@octobercms.com) ### Threat assessment: <img width="699" alt="Screen Shot 2021-02-07 at 11 50 35 PM" src="https://user-images.githubusercontent.com/7253840/107180881-51eaf000-699f-11eb-8828-333128faf2a6.png">

### Impact When logging out, the session ID was not invalidated. This is not a problem while the user is logged out, but as soon as the user logs back in the old session ID would be valid again; which means that anyone that gained access to the old session cookie would be able to act as the logged in user. This is not a major concern for the majority of cases, since it requires a malicious party gaining access to the session cookie in the first place, but nevertheless has been fixed. ### Patches Issue has been patched in Build 472 (v1.0.472) and v1.1.2. ### Workarounds Apply https://github.com/octobercms/library/commit/642f597489e6f644d4bd9a0c267e864cabead024 to your installation manually if unable to upgrade to Build 472 or v1.1.2. ### References - Reported by Anisio (Brazilian Information Security Analyst) - http://cve.circl.lu/cve/CVE-2021-3311 ### For more information If you have any questions or comments about this advisory: * Email us at [hello@octobercms.com](mailto:hello@octobercms.com) ### Threat assessment: <img width="699" alt="Screen Shot 2021-02-07 at 11 50 35 PM" src="https://user-images.githubusercontent.com/7253840/107180881-51eaf000-699f-11eb-8828-333128faf2a6.png">

Se detectó un problema en October hasta el build 471. Reactiva una ID de una sesión anterior (que había sido no válida después de cerrar la sesión) una vez que se produce un nuevo inicio de sesión.&#xa0;NOTA: esto viola el comportamiento de autenticación del archivo Auth/Manager.php previsto pero, cierto es que, solo es relevante si un ID de sesión antiguo es conocido por el atacante