The old D&D worlds forum known as The Piazza (which has Forgotten Realms, Arcane Age, Kara-Tur and Maztica subforums) has been infected by malware.
The administrator (Ashtagon) is working to find a solution and hopefully the site will be infection free within the next few days. The moderators of the site (including myself) are doing what we can to help (including warning people to avoid the site for now). The site has been marked as infected by Google and once the hackers are blocked it will probably take a day or so for them to retest the site and remove their malware warning.
It is probably best to avoid The Piazza until the situation is resolved. Hopefully Candlekeep has taken precautions against this sort of thing.