Riot Games has shed some light on the Anti-Cheat system that it uses for Valorant. According to the developers, Riot Games uses a a driver at system startup that it doesn’t scan anything. So yeah, the game actually installs an external program, however, players are free to remove it whenever they want.
As Riot Games explained:
“Vanguard contains a driver component called vgk.sys (similar to other anti-cheat systems). It’s the reason why the game needs to reboot your system after installing. Vanguard doesn’t consider the computer trusted unless the Vanguard driver is loaded at system startup. This part is less common for anti-cheat systems.
This is good for stopping cheaters because a common way to bypass anti-cheat systems is to load cheats before the anti-cheat system starts and either modify system components to contain the cheat or to have the cheat tamper with the anti-cheat system as it loads. Running the driver at system startup time makes this significantly more difficult.
We tried to be very careful with the security of the driver. We’ve had multiple external security research teams review it for flaws (we don’t want to accidentally decrease the security of the computer like other anti-cheat drivers have done in the past). We’re also following a least-privilege approach to the driver where the driver component does as little as possible preferring to let the non-driver component do the majority of work (also the non-driver component doesn’t run unless the game is running).”
Riot Games concluded that the driver component does not collect any information from your computer. Moreover, this driver does ot communicate over the network at all. Players can also remove it at will. If you’ve installed the game, Vangaurd will be as “Riot Vanguard” in Add/Remove programs.