Comodo Firewall Pro 2.4.18.184 and Comodo Personal Firewall 2.3.6.81, and probably older Comodo Firewall versions, do not properly test for equivalence of process identifiers for certain Microsoft Windows API functions in the NT kernel 5.0 and greater, which allows local users to call these functions, and bypass firewall rules or gain privileges, via a modified identifier that is one, two, or three greater than the canonical identifier.