new_audit: use a strong HSTS policy

cli/test/smokehouse/core-tests.js

@@ -21,6 +21,8 @@ import fpsMaxPassive from './test-definitions/fps-max-passive.js';
 import fpsScaled from './test-definitions/fps-scaled.js';
 import fpsOverflowX from './test-definitions/fps-overflow-x.js';
 import issuesMixedContent from './test-definitions/issues-mixed-content.js';
+import hstsFullyPresent from './test-definitions/hsts-fully-present.js';
+import hstsMissingDirectives from './test-definitions/hsts-missing-directives.js';
 import lanternFetch from './test-definitions/lantern-fetch.js';
 import lanternIdleCallbackLong from './test-definitions/lantern-idle-callback-long.js';
 import lanternIdleCallbackShort from './test-definitions/lantern-idle-callback-short.js';
@@ -79,6 +81,8 @@ const smokeTests = [
   fpsOverflowX,
   fpsScaled,
   issuesMixedContent,
+  hstsFullyPresent,
+  hstsMissingDirectives,
   lanternFetch,
   lanternIdleCallbackLong,
   lanternIdleCallbackShort,

cli/test/smokehouse/test-definitions/hsts-fully-present.js

@@ -0,0 +1,26 @@
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @type {Smokehouse.ExpectedRunnerResult}
+ * Expected Lighthouse results a site with full HSTS deployed.
+ */
+const expectations = {
+  lhr: {
+    requestedUrl: 'https://hstspreload.org/',
+    finalDisplayedUrl: 'https://hstspreload.org/',
+    audits: {
+      'has-hsts': {
+        score: null,
+      },
+    },
+  },
+};
+
+export default {
+  id: 'hsts-fully-present',
+  expectations,
+};

cli/test/smokehouse/test-definitions/hsts-missing-directives.js

@@ -0,0 +1,26 @@
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @type {Smokehouse.ExpectedRunnerResult}
+ * Expected Lighthouse results a site with HSTS header issues.
+ */
+const expectations = {
+  lhr: {
+    requestedUrl: 'https://developer.mozilla.org/en-US/',
+    finalDisplayedUrl: 'https://developer.mozilla.org/en-US/',
+    audits: {
+      'has-hsts': {
+        score: 1,
+      },
+    },
+  },
+};
+
+export default {
+  id: 'hsts-missing-directives',
+  expectations,
+};

core/audits/has-hsts.js

@@ -0,0 +1,210 @@
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {Audit} from './audit.js';
+import {MainResource} from '../computed/main-resource.js';
+import * as i18n from '../lib/i18n/i18n.js';
+
+const UIStrings = {
+  /** Title of a Lighthouse audit that evaluates the security of a page's HSTS header. "HSTS" stands for "HTTP Strict Transport Security". */
+  title: 'Use a strong HSTS policy',
+  /** Description of a Lighthouse audit that evaluates the security of a page's HSTS header. This is displayed after a user expands the section to see more. No character length limits. The last sentence starting with 'Learn' becomes link text to additional documentation. "HSTS" stands for "HTTP Strict Transport Security". */
+  description: 'Deployment of the HSTS header significantly ' +
+    'reduces the risk of downgrading of and eavesdropping attacks on HTTP connections. ' +
+    'A rollout in stages, starting with a low max-age is recommended. ' +
+    '[Learn what HSTS is.](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security)',
+  /** Summary text for the results of a Lighthouse audit that evaluates the HSTS header. This is displayed if no HSTS header is deployed. "HSTS" stands for "HTTP Strict Transport Security". */
+  noHsts: 'No HSTS header found',
+  /** Summary text for the results of a Lighthouse audit that evaluates the HSTS header. This is displayed if the preload directive is missing. "HSTS" stands for "HTTP Strict Transport Security". */
+  noPreload: 'No preload directive found',
+  /** Summary text for the results of a Lighthouse audit that evaluates the HSTS header. This is displayed if the includeSubDomains directive is missing. "HSTS" stands for "HTTP Strict Transport Security". */
+  noSubdomain: 'No includeSubDomains directive found',
+  /** Summary text for the results of a Lighthouse audit that evaluates the HSTS header. This is displayed if the max-age directive is missing. "HSTS" stands for "HTTP Strict Transport Security". */
+  noMaxAge: 'No max-age directive',
+  /** Summary text for the results of a Lighthouse audit that evaluates the HSTS header. This is displayed if the provided duration for the max-age directive is too low. "HSTS" stands for "HTTP Strict Transport Security". */
+  lowMaxAge: 'Max-age too low',
+  /** Table item value calling out the presence of a syntax error. */
+  invalidSyntax: 'Invalid syntax',
+  /** Label for a column in a data table; entries will be a directive of the HSTS header. "HSTS" stands for "HTTP Strict Transport Security". */
+  columnDirective: 'Directive',
+  /** Label for a column in a data table; entries will be the severity of an issue with the HSTS header. "HSTS" stands for "HTTP Strict Transport Security". */
+  columnSeverity: 'Severity',
+};
+
+const str_ = i18n.createIcuMessageFn(import.meta.url, UIStrings);
+
+class HasHsts extends Audit {
+  /**
+   * @return {LH.Audit.Meta}
+   */
+  static get meta() {
+    return {
+      id: 'has-hsts',
+      scoreDisplayMode: Audit.SCORING_MODES.INFORMATIVE,
+      title: str_(UIStrings.title),
+      description: str_(UIStrings.description),
+      requiredArtifacts: ['devtoolsLogs', 'URL'],
+    };
+  }
+
+
+  /**
+   * @param {LH.Artifacts} artifacts
+   * @param {LH.Audit.Context} context
+   * @return {Promise<{hstsHeaders: string[]}>}
+   */
+  static async getRawHsts(artifacts, context) {
+    const devtoolsLog = artifacts.devtoolsLogs[Audit.DEFAULT_PASS];
+    const mainResource =
+        await MainResource.request({devtoolsLog, URL: artifacts.URL}, context);
+
+    var hstsHeaders =
+        mainResource.responseHeaders
+            .filter(h => {
+              return h.name.toLowerCase() === 'strict-transport-security';
+            })
+            .flatMap(h => h.value.split(';'));
+
+    // Sanitize the header value / directives.
+    hstsHeaders = hstsHeaders.map(v => v.toLowerCase().replace(/\s/g, ''));
+
+    return {hstsHeaders};
+  }
+
+  /**
+   * @param {string} hstsDirective
+   * @param {LH.IcuMessage | string} findingDescription
+   * @param {LH.IcuMessage=} severity
+   * @return {LH.Audit.Details.TableItem}
+   */
+  static findingToTableItem(hstsDirective, findingDescription, severity) {
+    return {
+      directive: hstsDirective,
+      description: findingDescription,
+      severity,
+    };
+  }
+
+  /**
+   * @param {string[]} hstsHeaders
+   * @return {{score: number, results: LH.Audit.Details.TableItem[]}}
+   */
+  static constructResults(hstsHeaders) {
+    const rawHsts = [...hstsHeaders];
+    const allowedDirectives = ['max-age', 'includesubdomains', 'preload'];
+    const violations = [];
+    const warnings = [];
+    const syntax = [];
+
+    if (!rawHsts.length) {
+      return {
+        score: 0,
+        results: [{
+          severity: str_(i18n.UIStrings.itemSeverityHigh),
+          description: str_(UIStrings.noHsts),
+          directive: undefined,
+        }],
+      };
+    }
+
+    // No max-age is a violation and renders the HSTS header useless.
+    if (!hstsHeaders.toString().includes('max-age')) {
+      violations.push({
+        severity: str_(i18n.UIStrings.itemSeverityHigh),
+        description: str_(UIStrings.noMaxAge),
+        directive: 'max-age'
+      })
+    }
+
+    if (!hstsHeaders.toString().includes('includesubdomains')) {
+      // No includeSubdomains might be even wanted. But would be preferred.
+      warnings.push({
+        severity: str_(i18n.UIStrings.itemSeverityMedium),
+        description: str_(UIStrings.noSubdomain),
+        directive: 'includeSubDomains'
+      })
+    }
+
+    if (!hstsHeaders.toString().includes('preload')) {
+      // No preload might be even wanted. But would be preferred.
+      warnings.push({
+        severity: str_(i18n.UIStrings.itemSeverityMedium),
+        description: str_(UIStrings.noPreload),
+        directive: 'preload'
+      })
+    }
+
+    for (const actualDirective of hstsHeaders) {
+      // We recommend 2y max-age. But if it's lower than 1y, it's a violation.
+      if (actualDirective.includes('max-age') &&
+          parseInt(actualDirective.split('=')[1], 10) < 31536000) {
+        violations.push({
+          severity: str_(i18n.UIStrings.itemSeverityHigh),
+          description: str_(UIStrings.lowMaxAge),
+          directive: 'max-age'
+        })
+      }
+
+      // If there is a directive that's not an official HSTS directive.
+      if (!allowedDirectives.includes(actualDirective)) {
+        // max-age=<number> would always trigger.
+        if (actualDirective.includes('max-age')) {
+          continue;
+        }
+        syntax.push({
+          severity: str_(i18n.UIStrings.itemSeverityLow),
+          description: str_(UIStrings.invalidSyntax),
+          directive: actualDirective
+        })
+      }
+    }
+
+    const results = [
+      ...violations.map(
+          f => this.findingToTableItem(
+              f.directive, f.description,
+              str_(i18n.UIStrings.itemSeverityHigh))),
+      ...warnings.map(
+          f => this.findingToTableItem(
+              f.directive, f.description,
+              str_(i18n.UIStrings.itemSeverityMedium))),
+      ...syntax.map(
+          f => this.findingToTableItem(
+              f.directive, f.description,
+              str_(i18n.UIStrings.itemSeverityLow))),
+    ];
+    return {score: violations.length ? 0 : 1, results};
+  }
+
+  /**
+   * @param {LH.Artifacts} artifacts
+   * @param {LH.Audit.Context} context
+   * @return {Promise<LH.Audit.Product>}
+   */
+  static async audit(artifacts, context) {
+    const {hstsHeaders} = await this.getRawHsts(artifacts, context);
+    const {score, results} = this.constructResults(hstsHeaders);
+
+    /** @type {LH.Audit.Details.Table['headings']} */
+    const headings = [
+      /* eslint-disable max-len */
+      { key: 'description', valueType: 'text', subItemsHeading: {key: 'description'}, label: str_(i18n.UIStrings.columnDescription)},
+      { key: 'directive', valueType: 'code', subItemsHeading: {key: 'directive'}, label: str_(UIStrings.columnDirective)},
+      { key: 'severity', valueType: 'text', subItemsHeading: {key: 'severity'}, label: str_(UIStrings.columnSeverity)},
+      /* eslint-enable max-len */
+    ];
+    const details = Audit.makeTableDetails(headings, results);
+
+    return {
+      score,
+      notApplicable: !results.length,
+      details,
+    };
+  }
+}
+
+export default HasHsts;
+export {UIStrings};

core/config/default-config.js

@@ -192,6 +192,7 @@ const defaultConfig = {
     'valid-source-maps',
     'prioritize-lcp-image',
     'csp-xss',
+    'has-hsts',
     'script-treemap-data',
     'accessibility/accesskeys',
     'accessibility/aria-allowed-attr',
@@ -541,6 +542,7 @@ const defaultConfig = {
         {id: 'geolocation-on-start', weight: 1, group: 'best-practices-trust-safety'},
         {id: 'notification-on-start', weight: 1, group: 'best-practices-trust-safety'},
         {id: 'csp-xss', weight: 0, group: 'best-practices-trust-safety'},
+        {id: 'has-hsts', weight: 0, group: 'best-practices-trust-safety'},
         // User Experience
         {id: 'paste-preventing-inputs', weight: 3, group: 'best-practices-ux'},
         {id: 'image-aspect-ratio', weight: 1, group: 'best-practices-ux'},

core/scripts/i18n/collect-strings.js

@@ -729,6 +729,8 @@ function checkKnownFixedCollisions(strings) {
       'Back/forward cache is disabled due to a keepalive request.',
       'Consider uploading your GIF to a service which will make it available to embed as an HTML5 video.',
       'Consider uploading your GIF to a service which will make it available to embed as an HTML5 video.',
+      'Directive',
+      'Directive',
       'Document contains a $MARKDOWN_SNIPPET_0$ that triggers $MARKDOWN_SNIPPET_1$',
       'Document contains a $MARKDOWN_SNIPPET_0$ that triggers $MARKDOWN_SNIPPET_1$',
       'Document has a valid $MARKDOWN_SNIPPET_0$',
@@ -745,6 +747,8 @@ function checkKnownFixedCollisions(strings) {
       'Pages with an in-flight network request are not currently eligible for back/forward cache.',
       'Potential Savings',
       'Potential Savings',
+      'Severity',
+      'Severity',
       'The page was evicted from the cache to allow another page to be cached.',
       'The page was evicted from the cache to allow another page to be cached.',
       'Use $MARKDOWN_SNIPPET_0$ to detect unused JavaScript code. $LINK_START_0$Learn more$LINK_END_0$',