The vBulletin development team has identified a potential issue with the strength of password encryption in vBulletin and we are implementing a patch to address this issue.
In certain rare cases, hackers can exploit a non-vBulletin vector (such as a bad plug-in) to access the vBulletin password database and attempt to decrypt administrator and user passwords.
In the cases we have investigated, if hackers are able to successfully exploit the password database, they focus on administrator usernames and passwords. Since many administrators work on multiple vBulletin sites, the hackers then search all vBulletin sites for a particular administrator username and attempt to log in with the corresponding password. They then...