Hardening
Information disclosure
Don't advertise your stack.
What it is
Headers like Server, X-Powered-By and X-AspNet-Version reveal the exact software and versions you run.
Why it matters
Attackers use version banners to match your stack to known CVEs. Removing them raises the cost of targeting you.
Risk without it
A precise version banner turns generic scanning into a targeted exploit for a known vulnerability.
Recommended
Remove or genericise Server; delete X-Powered-By and framework version headers.
Set it
server_tokens off; proxy_hide_header X-Powered-By;