edaBit-coding-challenges/printf-Format-Security

printf Format Security

by Bryce Dixon tags: scope, control_flow, bugs

Summary

printf is a standard C function that's a great way to easily print data to the console using format specifiers. That being said, it's common knowledge that you should NEVER give a user the ability to directly set the first parameter of a function that can take format specifiers. To pass this challenge, you need to find out why users shouldn't be given full co

Instructions

printf is a standard C function that's a great way to easily print data to the console using format specifiers. That being said, it's common knowledge that you should NEVER give a user the ability to directly set the first parameter of a function that can take format specifiers.

To pass this challenge, you need to find out why users shouldn't be given full control of printf. A vulnerable function will take a string you provide and pass it to printf along with a value you need to modify.

Examples

// No examples! The fun is finding the exploit yourself!

Notes

A format specifier is a character set like %s or %f. Look for one that writes to memory.