Heavy PIE for a safe life

PIE is a delicious dish with various recipes, depending on the baker's choice and needs. Generally, a grandma with life experience knows which recipe for a PIE is full of flavor and baked with love, filling us with lovely, secure memories. AS WELL AS PIEs in computer security.

PIE refers to a Position Independent Executable, a type of program binary that can be loaded and executed at any memory address, rather than a fixed location. PIE enhances Address Space Layout Randomization (ASLR) by enabling executables to be loaded at random memory addresses, thereby strengthening defenses against memory attacks.

ASLR protects against exploits by randomizing the locations of segments, variables, and functions in memory. When a program loads, its segments are arranged in a fixed order, making exploits predictable and any predictable system state increases attack feasibility, ASLR disrupts this by randomizing the placement of code, increasing entropy, and making attacks such as buffer overflows less effective. Its success depends on the amount of randomness.

ASLR randomizes memory layout at runtime to prevent attackers from predicting memory addresses, significantly reducing the success of memory-based exploits. If an attacker can leak memory addresses, ASLR may be bypassed. Its effectiveness is more substantial when combined with PIE, which enables the OS to fully randomize the location of the program’s code in memory at runtime and allows executables to be relocated at runtime. Note that compile-time randomization is more effective than runtime randomization.

How to bake a PIE

• The executable is compiled with relative addressing instead of absolute addresses.

• When loaded, the OS can relocate the program to any random memory location; all internal references stay valid regardless of the program's placement.

Without PIE, ASLR provides only partial protection because the primary executable often remains at a fixed address. PIE allows the executable to be relocated to a random memory address at runtime, significantly increasing resistance to memory-based attacks, and protects the program.

Complex PIE strengthens program security by making executables fully relocatable, enabling full ASLR, preventing reliance on fixed memory addresses, and increasing resistance to memory-based attacks. Heavy PIE keeps you safe with minimal or stable performance overhead.

References:

[1] Bishop, M. Computer Security: Art and Science. Addison-Wesley.