🐦Stack canaries are randomly chosen numbers that sit between buffers and return addresses in functions.
🔒They prevent buffer overflow attacks by checking if their value has been modified before a return.
🚫Bypassing stack canaries can be done through stack leaks or guessing the value.
💡Guessing the value of a stack canary is impractical due to the large number of possibilities.
🔐Stack canaries provide a decent level of security in modern systems.
What are stack canaries?
—Stack canaries are randomly chosen numbers that act as a defense mechanism against buffer overflow attacks.
How do stack canaries prevent buffer overflows?
—Stack canaries check if their value has been modified before a return. If the value has changed, it indicates a buffer overflow, and the program can terminate to prevent further exploitation.
Can stack canaries be bypassed?
—Yes, stack canaries can be bypassed through stack leaks or by guessing the value. However, guessing the value is impractical due to the large space of possibilities.
Do stack canaries provide strong security?
—Stack canaries provide a decent level of security in modern systems, but they should be used in conjunction with other security measures.
Are stack canaries used in all systems?
—Stack canaries are commonly used in systems that are susceptible to buffer overflow attacks, but their implementation may vary depending on the specific system.
00:05In the early 1900s, coal miners started using canaries to detect carbon monoxide in mines.
01:24Stack canaries act as low-tech carbon monoxide detectors for computers, indicating buffer overflows.
02:59Two main ways to bypass stack canaries are through stack leaks or guessing the value.
03:48Stack canaries provide a decent level of security, but they can be bypassed in certain scenarios.
06:41Stack canaries are still used today and have good synergy with other security measures.
