securityEASYSECURITY DEBUGGING
Warm up with SSRF URL filter repair
Easy Security Basics arena: URL parsing, private network blocking, redirect handling, and allowlist policy
XP reward
95
Coins
8
Target time
15m
An image proxy fetches user-provided URLs and internal metadata endpoints are showing probe attempts. You are working inside a secure engineering review room, and the arena only clears when the result is safe, deterministic, and explainable.
Learning objective
Learn to apply URL parsing, private network blocking, redirect handling, and allowlist policy in a secure engineering review room while explaining the invariant, safety constraints, and hidden edge cases.
Mission order
Requests include hostnames, redirects, IPv6 literals, localhost aliases, and cloud metadata IPs. Implement the direct solution first, then document the one edge case that can break it. Submit the solution plus enough reasoning to pass hidden edge cases.Visible checks
reproduces the reported failure
Expected: minimal failing case
adds a regression test
Expected: test fails before fix
Clear requirements
- Demonstrates URL parsing, private network blocking, redirect handling, and allowlist policy
- Handles the visible sample and hidden edge cases
- Keeps output deterministic and explainable
- Avoids unsafe dynamic execution
Secure validation contract
Judge type
SECURITY DEBUGGING
Complexity target
Minimal reproduction, source-cause fix, and regression test
Workspace
Code editor
typescriptsafe mock judge
Charging editor core
Test Results
Run the visible checks when your first pass is ready.
Clear Protocol
1Read the scenario and restate the expected output shape.
2Run visible checks before chasing hidden edge cases.
3Use Genie for one nudge if stuck, then explain the invariant.
4Submit only when the result is deterministic and safe.
Rewards
XP
95
Coins
8
Mission Route
Hints
Hints are metered and logged for No Hint Hero runs.
Genie Mentor Core
Hint protocol / contextual guardrails active
Progressive hints
Failed-test aware
Solution guarded
Mission: security-easy-ssrf-url-filter0 attempts0 failed tests0 hints used
Progressive hint depth
Genie: Genie online. I use your mission, attempts, failed tests, hints, and path context to coach the next rep without dumping answers first.