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strict-csp-html-webpack-plugin

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Comparing version 1.0.1 to 1.0.2

2

package.json
{
"name": "strict-csp-html-webpack-plugin",
"version": "1.0.1",
"version": "1.0.2",
"description": "A webpack plugin that adds a hash-based strict CSP to help protect your site against XSS attacks.",

@@ -5,0 +5,0 @@ "main": "plugin.js",

@@ -45,8 +45,8 @@ /**

const scriptHashes = strictCspModule.hashAllInlineScripts();
const strictCsp = strictCspLib.StrictCsp.getStrictCsp(
scriptHashes,
this.options.enableTrustedTypes,
true,
this.options.enableUnsafeEval
);
const { enableTrustedTypes, enableUnsafeEval } = this.options;
const strictCsp = strictCspLib.StrictCsp.getStrictCsp(scriptHashes, {
enableBrowserFallbacks: true,
enableTrustedTypes,
enableUnsafeEval,
});
strictCspModule.addMetaTag(strictCsp);

@@ -67,5 +67,6 @@ htmlPluginData.html = strictCspModule.serializeDom();

(compilation) => {
const hook = typeof this.htmlWebpackPlugin.getHooks === 'function' ?
this.htmlWebpackPlugin.getHooks(compilation).beforeEmit : // html-webpack-plugin v4 and above
compilation.hooks.htmlWebpackPluginAfterHtmlProcessing; // html-webpack-plugin v3
const hook =
typeof this.htmlWebpackPlugin.getHooks === 'function'
? this.htmlWebpackPlugin.getHooks(compilation).beforeEmit // html-webpack-plugin v4 and above
: compilation.hooks.htmlWebpackPluginAfterHtmlProcessing; // html-webpack-plugin v3

@@ -72,0 +73,0 @@ hook.tapAsync(

# strict-csp-html-webpack-plugin
[Available on npm](https://www.npmjs.com/package/strict-csp-html-webpack-plugin).
[Available on npm](https://www.npmjs.com/package/strict-csp-html-webpack-plugin)
⚠️ This is experimental. Do not use in production. Make sure to check [what's not supported](https://github.com/google/strict-csp/issues?q=is%3Aissue+is%3Aopen+label%3Afeature).
⚠️ This is experimental. Make sure to check [what's not supported](https://github.com/google/strict-csp/issues?q=is%3Aissue+is%3Aopen+label%3Afeature). Keep in mind that the `Report-Only` mode is not supported here since the policy is added via a meta tag (`Content-Security-Policy-Report-Only` is unfortunately not supported in meta tags).
## What this plugin does: defense-in-depth against XSS 🛡
*💡 Not using webpack? Head over to [strict-csp](https://github.com/google/strict-csp/tree/main/strict-csp) instead. It's the bundler-agnostic library this webpack plugin is based on, and it enables you to easily set a strict CSP.*
Cross-site scripting (XSS)—the ability to inject malicious scripts into a web application—has been one of the biggest web security vulnerabilities for over a decade.
strict-csp-html-webpack-plugin helps protect your single-page application against XSS attacks. It does so by configuring a [strict Content-Security-Policy (CSP)](https://web.dev/strict-csp) for your application.
strict-csp-html-webpack-plugin helps protect your single-page application against XSS attacks. It does so by configuring a [strict Content-Security-Policy (CSP)](https://web.dev/strict-csp) for your web application.
A strict CSP, added in the form of a meta tag, looks as follows:
A strict CSP, added in the form of an HTML `meta` tag, looks as follows:

@@ -19,3 +20,3 @@ ```html

http-equiv="Content-Security-Policy"
content="script-src 'sha256-3uCZp...oQxI=' 'strict-dynamic'; style-src 'self' 'unsafe-inline'"
content="script-src 'sha256-3uCZp...oQxI=' 'strict-dynamic'; style-src 'self' 'unsafe-inline'">
</meta>

@@ -74,5 +75,69 @@ ```

| `enabled` | `true` | When `true`, activates the plugin. |
| `enableTrustedTypes` | `true` | When `true`, enables [trusted types](https://web.dev/trusted-types) for additional protections against DOM XSS attacks. |
| `enableTrustedTypes` | `false` | When `true`, enables [trusted types](https://web.dev/trusted-types) for additional protections against DOM XSS attacks. |
| `enableUnsafeEval` | `false` | When `true`, enables [unsafe-eval](https://web.dev/strict-csp/) in case you cannot remove all uses of `eval()`. |
## FAQ
### Does this plugin protect my users from XSS attacks?
A CSP offers an *extra* layer of security (also called "defense-in-depth" technique) to mitigate XSS attacks. It's not a replacement for properly escaping user-controlled data and sanitizing user input.
Now, this plugin sets a hash-based **strict** CSP. While this does remove several common XSS attack surfaces, it doesn't guarantee that your application is XSS-free.
To cover most of the XSS attack surface, we recommend to also enable [Trusted Types](https://web.dev/trusted-types/) (DOM XSS).
### Where should I use this plugin?
This plugin is best-suited for use in single-page applications that are served statically.
If you are rendering HTML on the server-side, you will also have to consider stored and reflected XSS. In this case we recommend using a [nonce-based strict CSP](https://web.dev/strict-csp#step-1:-decide-if-you-need-a-nonce-or-hash-based-csp) instead.
### How does this plugin, **strict**-csp-html-webpack-plugin, differ from [csp-html-webpack-plugin](https://www.npmjs.com/package/csp-html-webpack-plugin)?
This plugin **strict**-csp-html-webpack-plugin focuses on one thing: it mitigates XSS vulnerabilities. It does so by setting up a [strict CSP](https://web.dev/strict-csp), that is, an efficient defense-in-depth mechanism against XSS attacks.
It automatically sets up a secure CSP and frees you from manual configurations.
csp-html-webpack-plugin on the other hand, has a numbers of options to choose from. If you're using a CSP for other purposes than XSS mitigation, check out [csp-html-webpack-plugin](https://www.npmjs.com/package/csp-html-webpack-plugin). Note that at the moment, static nonces risk making csp-html-webpack-plugin's CSP bypassable, though this may be resolved in the future.
### I already have a CSP on my site, with an allowlist*. Should I consider using this plugin?
*An allowlist CSP looks as follows: `default-src https://cdn.example https://site1.example https://site2.example;`.
It depends.
If you're using your allowlist CSP purely to load scripts coming from a certain origin, you can keep using it.
But if you're relying on your allowlist CSP for XSS protection: migrate to the more secure strict CSP approach, and consider using this plugin to help you do so.
Allowlist-based CSP are not recommended anymore for XSS protection, because don't efficiently protect sites against XSS attacks: [research has shown that they can be bypassed](https://research.google/pubs/pub45542/). 🥲
They're also harder to maintain!
Instead, strict CSPs are now recommended, because they're both [more secure and easier to maintain than allowlist-based CSPs](https://web.dev/strict-csp/#why-a-strict-csp-is-recommended-over-allowlist-csps).
This plugin automatically adds a strict CSP to your application.
### Can this plugin slow down my site?
See [issue #15](https://github.com/google/strict-csp/issues/15).
### How does a strict CSP compare with subresource integrity (SRI)?
SRI can be used to ensure the integrity of scripts, e.g. to protect your site in case your CDN gets compromised.
However, SRI will not mitigate XSS caused by an injection vulnerability *in your own site*.
### Why should sourced scripts be replaced by an inline script?
A strict hash-based CSP allows certain scripts based on their hash.
However, Firefox ([bug](https://bugzilla.mozilla.org/show_bug.cgi?id=1409200)) and Safari (bug) do not support hashes for externally-sourced scripts⏤only for inline scripts.
Because this plugin aims at setting a CSP that helps protect your users in all browsers, it first transforms your externally-sourced scripts into an inline script.
### How does this plugin work?
strict-csp-webpack-plugin uses the [strict-csp](https://github.com/google/strict-csp/tree/main/strict-csp) custom library to form a strict CSP and hooks into `HtmlWebpackPlugin` to set up this CSP as a `meta` HTML tag.
Learn more about what the strict-csp library exactly does [here](https://github.com/google/strict-csp/tree/main/strict-csp).
**TL;DR: this library automates the steps to [add a hash-based strict CSP to your site](https://web.dev/strict-csp/#adopting-a-strict-csp).**
## Resources
* [Mitigate cross-site scripting (XSS) with a strict Content Security Policy (CSP)](https://web.dev/strict-csp/)
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