process - ie a running program – for data and code This memory consists of different segments • stack - for local variables
If we can make the memory segement used for stack non-executable, even if the code is injected into the stack, the code will not be able to execute This way,
26 sept 2019 · 2 store executable code somewhere in memory 3 use stack overflow to direct execution there The attack code is known as shellcode
C functions for memory management o malloc: allocate memory from the heap o free: deallocate memory from the heap 3 Code vs Executable vs Process
There are two types of memory allocation: stack memory and heap memory In It's a three line code, let's understand line by line how things execute
alization of stack and heap memory of a running pro- gram The approach is aimed at building a clear a heap The program area is where the code is loca-
The solution idea is to make the stack and heap non- executable, and executable code should only be found elsewhere in a process' address space • The Memory
Execution of a program is initially under the control of the operating system Revised Memory Layout Low Address High Address Memory Code Stack
The heap Special memory segments Wrapping up memory Reading the stack Execute expensive clean-up code per variable when the function returns
Code-Injection attacks Attack executable attack code injected into data memory invokes system calls directly Defence the kernel component of e-NeXSh ex-