Vac, Vac2 and Gameguard are (in my eyes) some of the toughest anticheat software, although disablers have been made for both Vac's people are too scared to use them incase it is detected and therefore results in a permanent ban and therefore costing the player money to get a new account. Gameguard is one of the toughest anticheat systems...
Trusting 'disablers' is a bad idea- they generally rely on the exact location of some conditional jump instruction somewhere in an specific version of a certain program. These are almost always updated constantly- often to include detection for the previous 'disabler'.
However, all these anticheat software addins are rendered almost completely useless when a
Shadow Walker rootkit is used. There are currently no publicly availible implementations of the technique (a good thing- sorry, greedy leachers); but some underground hacking groups have realised it's potential to evade direct memory scanning- and so have already developed their own versions. Hoglund- and some of the
rootkit staff used this powerful technique to sneak 'under the radar' of warden (WoW anticheat). Flawless is a strong word- but not far from the truth...Shadow Walking is a general, portable technique that- when done correctly; hides existing (already detected) trainers from all cheat detection memory scanners. If someone was to developer their own version- they could run every existing (detected) hack in VAC2 and never EVER have to worry about getting banned on their $4000 account.
Briefly- the method involves modifying the windows memory manager- to swap different physical page frames to virtual ones 'on the fly'- based on the context of the access (read/write or execution)... Very cool idea; check it out at the link above if you're interested
Subsky