CVE-2020-11069: Cross-Site Request Forgery in TYPO3 CMS
### Meta CVSS v3.1: AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C CWE-352 CWE-346
Problem It has been discovered that backend user interface and install tool are vulnerable to same-origin request forgery. A backend user can be tricked into interacting with a malicious resource an attacker previously managed to upload to the web server - scripts are then executed with the privileges of the victims' user session.
In a worst case scenario new admin users can be created which can directly be used by an attacker. The vulnerability is basically a cross-site request forgery (CSRF) triggered by a cross-site scripting vulnerability (XSS) - but happens on the same target host - thus, it’s actually a same-origin request forgery.
Malicious payload such as HTML containing JavaScript might be provided by either an authenticated backend user or by a non-authenticated user using a 3rd party extension - e.g. file upload in a contact form with knowing the target location.
The attacked victim requires an active and valid backend or install tool user sessions at the time of the attack to be successful.
Solution Update to TYPO3 versions 9.5.17 or 10.4.2 that mitigates the problem described.
Additional Considerations
The deployment of additional mitigation techniques is suggested as described below.
Sudo Mode Extension
This TYPO3 extension intercepts modifications to security relevant database tables, e.g. those storing user accounts or storages of the file abstraction layer. Modifications need to confirmed by again by the acting user with providing their password again - this technique is known as "sudo mode". This way unintended actions happening in the background can be mitigated.
https://github.com/FriendsOfTYPO3/sudo-mode https://extensions.typo3.org/extension/sudomode
Content Security Policy
Content Security Policies tell (modern) browsers how resources served a particular site are handled - it also it possible to disallow script executions for specific locations. In a TYPO3 context it is suggested to disallow direct script execution at least for locations /fileadmin/ and /uploads/.
in fileadmin/.htaccess <IfModule modheaders.c> Header add Content-Security-Policy "default-src 'self'; script-src 'none';" </IfModule>
Credits Thanks to Matteo Bonaker who reported this issue and to TYPO3 security team member Oliver Hader who fixed the issue.
References https://typo3.org/security/advisory/typo3-core-sa-2020-006
Other sources
In TYPO3 CMS 9.0.0 through 9.5.16 and 10.0.0 through 10.4.1, it has been discovered that the backend user interface and install tool are vulnerable to a same-site request forgery. A backend user can be tricked into interacting with a malicious resource an attacker previously managed to upload to the web server. Scripts are then executed with the privileges of the victims' user session. In a worst-case scenario, new admin users can be created which can directly be used by an attacker. The vulnerability is basically a cross-site request forgery (CSRF) triggered by a cross-site scripting vulnerability (XSS) - but happens on the same target host - thus, it's actually a same-site request forgery. Malicious payload such as HTML containing JavaScript might be provided by either an authenticated backend user or by a non-authenticated user using a third party extension, e.g. file upload in a contact form with knowing the target location. To be successful, the attacked victim requires an active and valid backend or install tool user session at the time of the attack. This has been fixed in 9.5.17 and 10.4.2. The deployment of additional mitigation techniques is suggested as described below. - Sudo Mode Extension This TYPO3 extension intercepts modifications to security relevant database tables, e.g. those storing user accounts or storages of the file abstraction layer. Modifications need to confirmed again by the acting user providing their password again. This technique is known as sudo mode. This way, unintended actions happening in the background can be mitigated. - https://github.com/FriendsOfTYPO3/sudo-mode - https://extensions.typo3.org/extension/sudomode - Content Security Policy Content Security Policies tell (modern) browsers how resources served a particular site are handled. It is also possible to disallow script executions for specific locations. In a TYPO3 context, it is suggested to disallow direct script execution at least for locations /fileadmin/ and /uploads/.
TYPO3-CORE-SA-2020-006: Same-Site Request Forgery to Backend User Interface
Affected Software
Event History
Frequently Asked Questions
What is the vulnerability ID of this TYPO3 vulnerability?
The vulnerability ID of this TYPO3 vulnerability is CVE-2020-11069.
What is the severity level of CVE-2020-11069?
The severity level of CVE-2020-11069 is high with a CVSS score of 8.8.
Which TYPO3 versions are affected by CVE-2020-11069?
TYPO3 versions 9.0.0 through 9.5.16 and 10.0.0 through 10.4.1 are affected by CVE-2020-11069.
What is the CWE ID associated with CVE-2020-11069?
The CWE ID associated with CVE-2020-11069 are 79, 352, and 346.
Where can I find more information about TYPO3 vulnerability CVE-2020-11069?
You can find more information about TYPO3 vulnerability CVE-2020-11069 on the TYPO3.org security advisory page and the TYPO3.CMS GitHub page.