VAC helps identify when cheats are installed and bans users from playing on VAC-secured servers; games include Counter-Strike, Half-Life 2: Deathmatch, Team Fortress 2 and more. Concerns arose after a post appeared on Reddit claiming that VAC reads every DNS cache entry and reports it back to Valve’s servers. According to Newell, cheat developers create DRM and anti-cheat codes to ensure payment.
“These cheats phone home to a DRM server that confirms that a cheater has actually paid to use the cheat,” Newell wrote. “VAC checked for the presence of these cheats. If they were detected VAC then checked to see which cheat DRM server was being contacted.
“This second check was done by looking for a partial match to those (non-web) cheat DRM servers in the DNS cache. If found, then hashes of the matching DNS entries were sent to the VAC servers. The match was double checked on our servers and then that client was marked for a future ban. Less than a tenth of one percent of clients triggered the second check. Five-hundred and seventy cheaters are being banned as a result.”
Newell added that this specific round was effective for 13 days — a “fairly typical” amount of time. Cheats on this “kernel-level” are costly to both create and detect, he continued.
“Our goal is to make them more expensive for cheaters and cheat creators than the economic benefits they can reasonably expect to gain,” Newell wrote.
The co-founder added that on the social engineering side, it is to a cheat developer’s advantage to spread mistrust in the system — in this case, Valve.