Cross-Site-Request-Forgery in Backend

> ### Meta > * CVSS: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C (8.2)

Problem

It has been discovered that the new TYPO3 v11 feature that allows users to create and share deep links in the backend user interface is vulnerable to cross-site-request-forgery.

The impact is the same as described in TYPO3-CORE-SA-2020-006 (CVE-2020-11069). However, it is not limited to the same site context and does not require the attacker to be authenticated. In a worst case scenario, the attacker could create a new admin user account to compromise the system.

To successfully carry out an attack, an attacker must trick his victim to access a compromised system. The victim must have an active session in the TYPO3 backend at that time.

The following Same-Site cookie settings in _$GLOBALS[TYPO3_CONF_VARS][BE][cookieSameSite]_ are required for an attack to be successful:

• _SameSite=_*strict*: malicious evil.example.org invoking TYPO3 application at good.example.org
• _SameSite=_*lax* or *none*: malicious evil.com invoking TYPO3 application at example.org

Solution

Update your instance to TYPO3 version 11.5.0 which addresses the problem described.

Credits

Thanks to Richie Lee who reported this issue and to TYPO3 core & security team members Benni Mack and Oliver Hader who fixed the issue.

References

• TYPO3-CORE-SA-2021-014
• CVE-2020-11069 reintroduced in TYPO3 v11.2.0