If you are talking about WoWUI's UICentral, as of a few days ago, it had a Trojan embedded in it. I think the WoWUI admins have uploaded a clean version. Check the UIC download page on WoWUI.
Depending on the mods you are updating you may want to look at WoW UI Updater (WUU). This open source program (written in Python) will update all WoW Addons except for ones hosted on WoWUI. So mods from Curse, WoWI, WoWAce will be updated as well as Auctioneer/Gatherer (direct from the dev's site), CTMod etc. This updater is also multi OS savvy as well.
The WUU thread can be found at WoWAce:
http://www.wowace.com/forums/index.php?topic=9814.0
I have been using an updater from the Getbuffed site (http:
www.getbuffed.com or
http://www.buffed.de). It auto updates my mods and check about once a day for updated mods. My only issue with this updater is it is all in German. Supposedly there is an English version however I have not found it. At least I can figure out German though.