CVE-2020-11067

In TYPO3 CMS 9.0.0 through 9.5.16 and 10.0.0 through 10.4.1, it has been discovered that backend user settings (in $BE_USER->uc) are vulnerable to insecure deserialization. In combination with vulnerabilities of third party components, this can lead to remote code execution. A valid backend user account is needed to exploit this vulnerability. This has been fixed in 9.5.17 and 10.4.2.

Weakness

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Software

Potential Mitigations

• Make fields transient to protect them from deserialization.
• An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/586.html

References

• https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-2wj9-434x-9hvp
• https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-2wj9-434x-9hvp