CVE-2020-35938

PHP Object injection vulnerabilities in the Post Grid plugin before 2.0.73 for WordPress allow remote authenticated attackers to inject arbitrary PHP objects due to insecure unserialization of data supplied in a remotely hosted crafted payload in the source parameter via AJAX. The action must be set to post_grid_import_xml_layouts.

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://www.wordfence.com/blog/2020/10/high-severity-vulnerabilities-in-post-grid-and-team-showcase-plugins/
• https://www.wordfence.com/blog/2020/10/high-severity-vulnerabilities-in-post-grid-and-team-showcase-plugins/