There's mention of VAC several times on the page but the steam page says nothing about Ghosts having VAC and if you go here http://store.steampowered.com/search/?category2=8 it's a list of vac enabled games. Ghosts doesn't come up. I've heard mention of them using their own anti-cheat system and came across this: http://www.shacknews.com/article/81471/call-of-duty-ghosts-will-have-dedicated-servers-on-all "In addition, Ghosts will feature new anti-cheat measures. Rubin also says". VAC isn't new.
Topic on Talk:Call of Duty: Ghosts
AFAIK, steam can monitor memory injections. That is why, when people try to use pirated games with steam (i.e. fake AppID to play via Tunngle/Hamachi) it is usually advised not use your main account, but a separate one without games. Per se, it's not VAC, but steam itself that can ban you. So correct the mentions as you see fit.