Unfortunately there is another rash of virus attacks via WoW AddOn websites. This time the culprits have struck WoWinterface, but thankfully this issue was taken care of fairly quickly on their end. Slouken posted a warning about the issue and Cairenn -- the WoWI Administrator -- created a thread, alerting everyone of the known file versions that are trojans. She's also provided a great recap of steps to take if you've been infected by this trojan, so please be sure to take a look at the thread -- especially if you use auto updater programs to download your AddOns from your favorite websites.
We'd like to echo what Slouken says in his post: do not download an AddOn package that contains an executable file of any type; if you absolutely must, be sure the source is trusted beforehand.
In response to this, we here at Curse are going to be putting our executable acceptance on lockdown temporarily until this situation is under better control. We apologize in advance for any delays this places on everyone's packages being available on the website, but ensuring the safety of players who visit Curse is our top priority when it comes to executable files.