Blocking Internal Metadata Forgery and Redirect Escapes
An application fetches a web address supplied by a user, and an attacker points it at an internal cloud address or uses a redirect to reach private internal services. The scope guard blocks external hosts and redirect hops while compiling a strict address allowlist rule.
Server-side request forgery occurs when a backend service fetches a network address provided by an external caller without restricting the destination subnet range. Attackers supply loopback addresses, link-local cloud metadata endpoints, or internal service ports to read credentials from behind the firewall.
1. Interception and Rule Synthesis Schematic for SSRF-INT
Verification sequence for SSRF-INT: candidate probe inspection by wire rule SEC-ZD-SSRF-01, differential confirmation via witness 275905904349f049, and compilation of gateway contract IMMUNE-SSRF-27590590.
2. In-Path Mutation Blocking and Paired Decoy Verification (SSRF-INT)
The transport layer enforces boundary control through ScopeGuard and ScopedRedirectHandler under rule SEC-ZD-SSRF-01. Every outbound request and every intermediate 301, 302, 307, or 308 redirect hop is validated against the local testbed allowlist before a connection is opened.
On the benchmark suite, the verifier tests both direct private-network fetches and redirect-chain bypasses against vulnerable and hardened handlers. The testbed run produces two true positives, zero false positives, two true negatives, and zero false negatives.
Class Identifier: SSRF-INT (ssrf)
Execution Mode: Active Safe Probing (AUTO_SCAN)
Candidate Probe: POST /api/v1/vuln/ssrf/webhook {"callback_url": "http://169.254.169.254/latest/meta-data/"}
Blocked Mutation: 302 Redirect -> https://external-bank.example.com/admin
Stand Confusion Matrix: TP = 2, FP = 0, TN = 2, FN = 0 (FPR = 0.0%)
Wire Sandbox Rule: SEC-ZD-SSRF-01
Formal Witness Hash: 275905904349f049
Compiled Sentinel Rule: IMMUNE-SSRF-27590590 (synthesis time 20 µs)3. Automatic Synthesis of Gateway Rule IMMUNE-SSRF-27590590
Witness 275905904349f049 compiles into contract IMMUNE-SSRF-27590590 within 20 microseconds. The contract blocks link-local ranges, private subnets, loopback aliases, and unverified redirect chains inside mcp-sentinel.
4. Related Benchmark Classes on the INDRA Stand
INJ-SQL: Database Query InjectionINJ-CMD: Operating System Command InjectionDIR-TRV: Filesystem Path TraversalAUTH-BOLA: Broken Object Level AuthorizationSEC-LEAK: Authentication Token and Secret ExposureHDR-SEC: Missing Transport and Framing Security HeadersDOS-RSRC: Computational Resource Exhaustion (Isolated Lab Mode)