CVE-2020-15099: Exposure of Sensitive Information to an Unauthorized Actor in TYPO3 CMS
### Meta CVSS: 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) CWE-20, CWE-200
Problem In case an attacker manages to generate a valid cryptographic message authentication code (HMAC-SHA1) - either by using a different existing vulnerability or in case the internal encryptionKey was exposed - it is possible to retrieve arbitrary files of a TYPO3 installation. This includes the possibility to fetch typo3conf/LocalConfiguration.php which again contains the encryptionKey as well as credentials of the database management system being used.
In case a database server is directly accessible either via internet or in a shared hosting network, this allows to completely retrieve, manipulate or delete database contents. This includes creating an administration user account - which can be used to trigger remote code execution by injecting custom extensions.
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.
References TYPO3-CORE-SA-2020-007
Other sources
In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.20, and greater than or equal to 10.0.0 and less than 10.4.6, in a case where an attacker manages to generate a valid cryptographic message authentication code (HMAC-SHA1) - either by using a different existing vulnerability or in case the internal encryptionKey was exposed - it is possible to retrieve arbitrary files of a TYPO3 installation. This includes the possibility to fetch typo3conf/LocalConfiguration.php, which again contains the encryptionKey as well as credentials of the database management system being used. In case a database server is directly accessible either via internet or in a shared hosting network, this allows the ability to completely retrieve, manipulate or delete database contents. This includes creating an administration user account - which can be used to trigger remote code execution by injecting custom extensions. This has been patched in versions 9.5.20 and 10.4.6.
TYPO3-CORE-SA-2020-007: Potential Privilege Escalation
Affected Software
Event History
Frequently Asked Questions
What is the vulnerability ID of TYPO3-CORE-SA-2020-007?
The vulnerability ID of TYPO3-CORE-SA-2020-007 is CVE-2020-15099.
What is the severity of CVE-2020-15099?
The severity of CVE-2020-15099 is high (8.1).
What is the affected software version range for TYPO3-CORE-SA-2020-007?
The affected software version range for TYPO3-CORE-SA-2020-007 is greater than or equal to 9.0.0 and less than 9.5.20, and greater than or equal to 10.0.0 and less than 10.4.6.
How can an attacker exploit CVE-2020-15099?
In a case where an attacker manages to generate a valid cryptographic message authentication code (HMAC-SHA1) - either by using a different existing vulnerability or in case they obtain a valid HMAC-SHA1 code from another source.
Where can I find more information about TYPO3-CORE-SA-2020-007?
You can find more information about TYPO3-CORE-SA-2020-007 at the TYPO3 security advisory page: https://typo3.org/security/advisory/typo3-core-sa-2020-007