Īdditionally, some versions of GameGuard had an unpatched privilege escalation bug, allowing any program to issue commands as if they were running under an Administrator account. Since GameGuard monitors any changes in the computer's memory, it will cause performance issues when the protected game loads multiple or large resources all at once. If set, GameGuard blocks any installation or activation of hardware and peripherals (e.g., a mouse) while the program is running. Since GameGuard essentially works like a rootkit, players may experience unintended and potentially unwanted side effects. GameGuard hides the game application process, monitors the entire memory range, terminates applications defined by the game vendor and INCA Internet to be cheats ( QIP for example ), blocks certain calls to Direct X functions and Windows APIs, keylogs keyboard input, and auto-updates itself to change as new possible threats surface.
GameGuard uses rootkits to proactively prevent cheat software from running. The software is considered to be one of three software programs which "dominate the online game security market". nProtect GameGuard provides B2B2C (Business to Business to Consumer) security services for online game companies and portal sites. It is widely installed in many online games to block possibly malicious applications and prevent common methods of cheating. NProtect GameGuard (sometimes called GG) is an anti-cheating rootkit developed by INCA Internet.