How can we prevent format string vulnerabilities ?

Preventing format string vulnerabilities :

1.Always specify a format string as part of the program, not as an input:

• Imagine you have a program that uses format strings, like “%s”. Instead of letting users input the format string, make it a fixed part of your code.
• Example: Instead of taking a user input for the format string, use printf("Hello, %s!\n", name); where “%s” is part of the code, not something a user can control.

2. Make the format string a constant:

• Constants are values that don’t change during the program’s execution. If possible, use constants for your format strings.
• Example: Instead of printf(format, data);, use printf("%s", data); where “%s” is a constant format string.

3. If the above two practices are not possible, use defenses such as Format_Guard:

• Sometimes, you might need user input as part of the format string. In such cases, use additional defenses or tools like Format_Guard to ensure that the input is safe.
• Example: If you have to use user input in a format string, make sure it’s sanitized and doesn’t contain any malicious characters or sequences.