| Program shepherding is a method for monitoring control flow transfers during program execution to enforce security policies. Program shepherding provides three techniques as building blocks for security policies. First, shepherding can restrict execution privileges on the basis of code origins. This distinction can ensure that malicious code masquerading as data is never executed, thwarting a large class of security attacks. Second, shepherding can restrict control transfers based on instruction class, source, and target. For example, shepherding can forbid execution of shared library code except through declared entry points, and can ensure that a return instruction only targets the instruction after a call. Finally, shepherding guarantees that sandboxing checks placed around any type of program operation will never be bypassed. |
