CVE-2021-25294

OpenCATS through 0.9.5-3 unsafely deserializes index.php?m=activity requests, leading to remote code execution. This occurs because lib/DataGrid.php calls unserialize for the parametersactivity:ActivityDataGrid parameter. The PHP object injection exploit chain can leverage an __destruct magic method in guzzlehttp.

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/snoopysecurity/snoopysecurity.github.io/blob/master/web-application-security/2021/01/16/09_opencats_php_object_injection.html
• https://snoopysecurity.github.io/web-application-security/2021/01/16/09_opencats_php_object_injection.html
• https://www.opencats.org/news/
• https://github.com/snoopysecurity/snoopysecurity.github.io/blob/master/web-application-security/2021/01/16/09_opencats_php_object_injection.html
• https://snoopysecurity.github.io/web-application-security/2021/01/16/09_opencats_php_object_injection.html
• https://www.opencats.org/news/