include::../description.adoc[]

include::../ask-yourself.adoc[]

include::../recommended.adoc[]

== Sensitive Code Example

In Express.js application the code is sensitive if the https://www.npmjs.com/package/expect-ct[expect-ct] middleware is disabled:

----
const express = require('express');
const helmet = require('helmet');

let app = express();

app.use(
    helmet({
      expectCt: false // Sensitive
    })
);
----

== Compliant Solution

In Express.js application the https://www.npmjs.com/package/expect-ct[expect-ct] middleware is the standard way to implement expect-ct. Usually, the deployment of this policy starts with the report only mode (``++enforce: false++``) and with a low ``++maxAge++`` (the number of seconds the policy will apply) value and next if everything works well it is recommended to block future connections that violate Expect-CT policy (``++enforce: true++``) and greater value for maxAge directive:

----
const express = require('express');
const helmet = require('helmet');

let app = express(); 

app.use(helmet.expectCt({
  enforce: true,
  maxAge: 86400
})); // Compliant
----

include::../see.adoc[]