A stack canary can help detect a buffer overflow if it is placed before the return address and checked before returning.

### Why this is right The material describes placing a canary in front of the return address. If an overflow reaches and changes the return address, it should also overwrite the canary, which can be checked before the function returns. ### The concept A canary is a value used to detect certain memory overwrites. It does not prevent every memory error, but it can reveal that a stack overwrite occurred before the program uses the return address. ### The other options - **False**: incorrect because the material specifically describes this placement and check as a mitigation. ### Terms - **Stack canary**: a marker checked to detect certain stack overwrites. - **Return address**: a saved location used to continue program execution. ### Remember A canary is useful only if the program checks it before trusting affected control data.