Format String Attack

A Format string attack is a cyberattack that takes advantage of vulnerabilities inside the software’s format string operations. The hackers deftly modify the input for those specific operations, giving themselves access to change the data in random memory spots.

This results in data leaks, disrupted service and even malicious code getting executed remotely.

Examples of format string attacks

  • Information disclosure: A hacker designs a malicious format string to read sensitive information from the application’s memory — information like user credentials or private keys.
  • Denial of service: With the use of a malicious format string, the hacker can execute a buffer overflow, which may result in the application or even the entire system crashing.
  • Remote code execution: A master hacker can modify the format string to overwrite a function’s return address, causing the program to execute malicious code.

How to prevent format string attacks

  • Use secure coding practices, like properly using format string functions and input validation.
  • Frequently update device software and install security updates to fix known weaknesses.
  • Set up protection mechanisms for runtime, such as address space layout randomization (ASLR) to ensure exploitation won’t be as easy.
  • Install VPNs to encrypt your internet connection and limit the risk of attacks designed to exploit vulnerabilities in the format string.