vulnerable.c:

Simple program that expects an input from the user and checks if the input matches the expected pattern provided by a regular expression.
The program prints a message indicating whether the input matches the pattern or not. 

exploit.sh:

This exploit takes advantage of vulnerable.c's permissive regex and provides a very large input, causing catastrophic backtracking.
Every second, it displays the process resource usage.   

exploit_long.sh:

This exploit works exactly like exploit.sh, except that it provides an even larger input, causing a bigger burden on the CPU. 
WARNING: Run at your own risk. Running this may disconnect an ssh connection to the Linux servers  

Make sure all source files are within your working directory.

To run vulnerable.c:

$ make

$ ./vulnerable

To run exploit.sh:

$ sh exploit.sh

To run exploit_long.sh:

$ sh exploit_long.sh