- Component Type: TYPO3 CMS
- Subcomponent: Backend User Interface (ext:backend)
- Release Date: July 28, 2020
- Vulnerability Type: Sensitive Information Disclosure
- Affected Versions: 9.0.0-9.5.19, 10.0.0-10.4.5
- Severity: High
- Suggested CVSS: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
- References: CVE-2020-15098, CWE-325, CWE-20, CWE-200, CWE-502
Problem Description
It has been discovered that an internal verification mechanism can be used to generate arbitrary checksums. This allows to inject arbitrary data having a valid cryptographic message authentication code (HMAC-SHA1) and can lead to various attack chains as described below.
- TYPO3-CORE-SA-2020-007, CVE-2020-15099: Potential Privilege Escalation
- the database server used for a TYPO3 installation must be accessible for an attacker (either via internet or shared hosting network)
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C (7.5, high)
- TYPO3-CORE-SA-2016-013, CVE-2016-5091: Insecure Deserialization & Remote Code Execution
- an attacker must have access to at least one Extbase plugin or module action in a TYPO3 installation
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C (9.1, critical)
The overall severity of this vulnerability is high (8.2) based on mentioned attack chains and the requirement of having a valid backend user session (authenticated) to successfully exploit this vulnerability.
Solution
Update to TYPO3 versions 9.5.20 or 10.4.6 that fix the problem described.
Credits
Thanks to TYPO3 security team member Oliver Hader who reported and fixed the issue.
General Advice
Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list.
General Note
All security related code changes are tagged so that you can easily look them up in our review system.