Which advanced session hijacking technique is hardest to detect and mitigate in a remote-access environment?

ARP spoofing–based session hijacking is identified in CEH v13 Web Application and Network Attacks as one of the most stealthy and difficult-to-detect session compromise techniques, especially within internal or VPN-connected networks.

In ARP spoofing, attackers poison ARP caches to position themselves as a man-in-the-middle (MitM). Once in place, they can silently intercept, modify, or replay session data—even when encryption is used—by redirecting traffic transparently between endpoints.

Option A (sidejacking) is mitigated by HTTPS. Option C (session guessing) is noisy and detectable. Option D (cookie poisoning) relies on weak validation and is easier to detect via integrity checks.

CEH v13 highlights ARP spoofing as particularly dangerous because:

It exploits trusted local network behavior

It does not require breaking encryption directly

It is often invisible to users and applications

Therefore, Option B is the most challenging to detect and mitigate and is the correct answer.