SafeGuard Inc.

Comprehensive and Detailed Explanation (ECIH-aligned):

SSRF vulnerabilities allow attackers to coerce a server into making unauthorized internal or external requests. The ECIH Web Application Security module states that controlling outbound traffic is the most effective mitigation against SSRF.

Option D is correct because restricting outbound traffic ensures that even if an SSRF flaw exists, the server cannot access internal resources or attacker-controlled endpoints. ECIH emphasizes network-level egress filtering as a primary defensive control for SSRF.

Option A reduces attack surface but does not stop exploitation. Option B addresses client-side risks, not server-side requests. Option C improves detection but does not prevent exploitation.

Thus, outbound traffic restriction is the priority mitigation measure.