How do you analyze buffer overflow exploits in a web server

Question

I am researching buffer overflow vulnerabilities in web servers and want to understand how to analyze exploits. My main questions are:

• How to detect signs of buffer overflow attacks in logs and crash reports?
• What tools (e.g., GDB, Valgrind, ASAN) are useful for analyzing exploited binaries?
• How attackers craft payloads and bypass security mechanisms like DEP and ASLR?

A practical example of analyzing a buffer overflow attack in a controlled environment would be helpful.