Roll out CSP with a reviewable enforcement plan
Move a Content Security Policy from observation to enforcement. Track script owners, violation causes, staged rollout decisions, and rollback evidence.
A Content Security Policy rollout should end with an enforced policy and an explanation of its exceptions. Collecting reports indefinitely is not the same outcome. Name the pages and business journeys covered by the rollout before changing directives. Account recovery, payment handoffs, and administrative screens often load different resources from the homepage.
OWASP distinguishes enforced CSP from report-only policy. Use report-only observations to investigate compatibility, while keeping output encoding and other primary defenses in place.
Assign each resource an owner
Inventory scripts, styles, frames, connections, and form destinations by route class. Identify inline code generated by the framework as well as third-party assets. A request in a browser trace is evidence of a dependency, not automatic approval to allow it.
| Observation | Investigation | Recorded decision |
|---|---|---|
| Inline application script | Check framework nonce or hash support | Approved delivery method |
| Vendor connection | Confirm purpose and data sent | Named owner and exact destination |
| Browser extension report | Reproduce in a clean profile | Exclude from application exception |
| Unexpected frame | Trace the initiating feature | Remove or approve a bounded use case |
Keep the inventory tied to a release. A policy based on an old asset graph can fail during a later deployment even if no policy text changed.
Triage reports before widening rules
Treat violation reports as untrusted input. Limit their size and retention, and do not display submitted fields as raw HTML. Group by route and blocked resource without retaining unnecessary user identifiers.
Reproduce a suspected application break in an authorized clean browser session. Check whether the violation represents essential behavior, obsolete code, or an unexpected dependency. Prefer removing unnecessary execution paths to adding a broad source exception. Avoid changing several directives at once when you need to identify the cause of a failure.
Define the enforcement gate
Choose representative journeys, supported browsers, and a limited deployment group. Record the tested policy, release identifier, successful workflows, and remaining exceptions. Move that policy to enforcement only when the accountable owner accepts the evidence.
Prepare a rollback that restores the last reviewed policy rather than removing all protection. Monitor real failures during the agreed rollout window. A quiet report stream alone cannot prove coverage: reporting can fail, users may not exercise a route, and some code paths may be absent from the sample. Recheck the inventory when the application adds a new script, frame, or external connection.
Find the gaps before your next launch
Use the release checklist to identify changed security boundaries and missing evidence. Discuss the application paths you want reviewed before launch.