Race Condition Exploits Lab

Race Condition Exploits Lab

In this lab, we will simulate race condition exploits in multithreaded applications.

Lab Activities:

1. Creating Vulnerable C Program:

First, let's create a vulnerable C program with a race condition vulnerability.

  #include <stdio.h>
  #include <stdlib.h>
  #include <pthread.h>

  int global_variable = 0;

  void *thread_function(void *arg) {
      int *increment = (int *)arg;
      global_variable += *increment;
      return NULL;
  }

  int main() {
      pthread_t threads[2];
      int increments[] = {1, -1};

      for (int i = 0; i < 2; i++) {
          pthread_create(&threads[i], NULL, thread_function, (void *)&increments[i]);
      }

      for (int i = 0; i < 2; i++) {
          pthread_join(threads[i], NULL);
      }

      printf("Global variable value: %d\n", global_variable);

      return 0;
  }
  

Save the above code to a file named vulnerable.c and compile it with the following command:

$ gcc -o vulnerable -pthread vulnerable.c

2. Writing Exploit Script:

Now, let's write an exploit script in Python to simulate the race condition exploit.

  import subprocess
  import threading

  # Function to repeatedly execute the vulnerable program
  def execute_vulnerable():
      subprocess.run(['./vulnerable'])

  # Create multiple threads to execute the vulnerable program concurrently
  num_threads = 10
  threads = []
  for _ in range(num_threads):
      t = threading.Thread(target=execute_vulnerable)
      threads.append(t)
      t.start()

  # Wait for all threads to complete
  for t in threads:
      t.join()
  

Explanation of the Python script:

• We define a function to repeatedly execute the vulnerable program.
• We create multiple threads to execute the vulnerable program concurrently.
• Each thread executes the execute_vulnerable() function.
• We start all threads and wait for them to complete.

3. Exploiting the Vulnerability:

Execute the Python script to simulate the race condition exploit:

$ python exploit.py

Once executed, you should observe different values of the global variable due to the race condition, demonstrating the successful simulation of the exploit.