CVE-2023-34253 Information

Description

Grav is a file-based Web platform. Prior to version 1.7.42 the denylist introduced in commit 9d6a2d to prevent dangerous functions from being executed via injection of malicious templates was insufficient and could be easily subverted in multiple ways – (1) using unsafe functions that are not banned (2) using capitalised callable names and (3) using fully-qualified names for referencing callables. Consequently a low privileged attacker with login access to Grav Admin panel and page creation/update permissions is able to inject malicious templates to obtain remote code execution. A patch in version 1.7.42 improves the denylist.

Reference

https://www.github.com/getgrav/grav/commit/9d6a2dba09fd4e56f5cdfb9a399caea355bfeb83 https://github.com/getgrav/grav/blob/1.7.40/system/src/Grav/Common/Utils.php#L1952-L2190 https://huntr.dev/bounties/3ef640e6-9e25-4ecb-8ec1-64311d63fe66/ https://github.com/getgrav/grav/security/advisories/GHSA-j3v8-v77f-fvgm https://github.com/getgrav/grav/commit/71bbed12f950de8335006d7f91112263d8504f1b