The Gutenberg Template Library & Redux Framework plugin <= 4.2.11 for WordPress registered several AJAX actions available to unauthenticated users in the includes
function in redux-core/class-redux-core.php
that were unique to a given site but deterministic and predictable given that they were based on an md5 hash of the site URL with a known salt value of β-reduxβ and an md5 hash of the previous hash with a known salt value of β-supportβ. These AJAX actions could be used to retrieve a list of active plugins and their versions, the siteβs PHP version, and an unsalted md5 hash of siteβs AUTH_KEY
concatenated with the SECURE_AUTH_KEY
.