machenjie web-security
Registry Trigger
Use when
- review changed web routes from browser or server trust boundary to rendering state-changing fetch upload redirect cross-origin embedding or protected-action sinks
Do not use when
- no task-local reachable web boundary or sink behavior changes
Skill Role
Trace web-controlled sources to render, navigation, state-change, fetch, upload, cross-origin, cookie, and embedding sinks with control-placement and bypass evidence. Exclude general permission and credential policy.
High-Value Rules
- Trace changed routes from source to sink. Identify attacker-controlled values, browser or server transformations, framework defaults, trust transitions, reachable sinks, and alternate encoded or nested paths before selecting a control.
- Match rendering protection to context. Preserve contextual escaping, sanitization, trusted-template boundaries, URL and style handling, and script or markup policy for the actual sink; avoid decoding or concatenation after validation.
- Protect state-changing requests at the authority boundary. Combine authenticated context with current request-integrity, origin, cookie, method, and object-authorization controls without treating browser UI or route guards as enforcement.
- Constrain server-side fetching and navigation. Validate destinations against owned policy, re-check redirects and resolved addresses, block credential forwarding and internal reachability, and preserve safe recovery for rejected targets.
- Treat uploads and downloads as active content boundaries. Bound type, size, name, path, archive expansion, scanning, storage authority, rendering disposition, and retrieval authorization according to reachable abuse.
- Define cross-origin and embedding behavior narrowly. Derive origin, credential, header, method, framing, opener, and message-channel policy from current consumers and reject ambient wildcard trust.
- Prove denial and bypass paths. Exercise alternate encodings, redirects, stale sessions, direct routes, nested payloads, mixed content, unauthorized objects, and deployment policy relevant to the changed sink.
Anti-Patterns
- Apply one generic sanitizer or allowlist before later decoding, templating, redirect, or parser transformations change the context.
- Trust client validation, hidden UI, same-origin appearance, internal hostnames, file extensions, or authenticated identity as sufficient sink protection.
- Claim a framework default or response header is deployed protection without route and environment evidence.
Stop Conditions
Escalate when source-to-sink reachability is unknown, state change lacks request integrity or object authorization, or server fetch can reach untrusted destinations. Also escalate when active-content handling is ambiguous, cross-origin credentials broaden, or deployed control and bypass behavior cannot be verified.
Output Contract
- web-security decision with reachable sources and sinks, contextual controls, state-change integrity, fetch and upload boundaries, cross-origin behavior, denial and bypass evidence, and proof limits
Targeted References
| Path | Type | Load when | Do not load when | Required by | Required output |
|---|---|---|---|---|---|
| benchmarks and patterns | benchmark-pattern | competing render browser-state fetch upload navigation cross-origin embedding response-policy or protected-route patterns remain viable | one bounded web decision is already complete from the root contract | analysis-agent, task-agent, review-agent | option-comparison, selected-approach |
| checklist | decision-checklist | several reachable web surfaces and their handoffs must close together | one bounded web surface is already complete from the root contract | analysis-agent, task-agent, review-agent | checklist-result, residual-risk |
| evidence patterns | evidence-pattern | route reachability control placement framework behavior denial bypass deployment or residual-scope claims need fresh proof | no task-local web-security claim awaits proof | analysis-agent, task-agent, review-agent | evidence-record, proof-limit, residual-risk |