No unsafe-inline vs UpdraftPlus

Content Security Policy (CSP) is a computer security standard introduced to prevent cross-site scripting (XSS), clickjacking and other code injection attacks resulting from execution of malicious content in the trusted web page context. Cross-site scripting (XSS) is a type of security vulnerability that can be found in some web applications. XSS attacks enable attackers to inject client-side scripts into web pages viewed by other users. A cross-site scripting vulnerability may be used by attackers to bypass access controls like the same-origin policy. Looking at National Vulnerability Database run by US NIST, more than 1100 (November 2025) vulnerabilities are reported as XSS for WordPress’ plugins and themes. Keeping your site up-to-date with the latest versions of plugins and themes is the first line of defense to ensure your site’s security. The second thing to do, is to deploy a strict Content Security Policy. The main problem The main problem with Content Security Policies implemented in the real world is that they are too weak to really protect your site and that many of them can be trivially bypassed by an attacker. The proposed solution Google researchers recommend, instead of whole host whitelisting, to activate individual scripts via a CSP nonces approach. In addition, in order to facilitate the adoption of nonce-based CSP, they proposed the ’strict-dynamic’ keyword. The problem(s) with CSP in WordPress Manual creation of a policy Usually, a WordPress project is a mix of code written by different authors who contributed to the Core and or wrote plugins and themes. If it is possible to whitelist every external script loaded from a , the real truth is that in a WordPress project you can have dozens of those scripts included with your plugins and calculate a cryptographic hash for each of them to be included in your CSP header can be a frustrating job. However, there are many browser extensions and WordPress’ plugins that can help you in this job. Inline scripts WordPress core, and plugins, use inline scripts. For these scripts, you can compute hashes to be inserted manually into your policy, only if these scripts do not change at any page load. Unfortunately, this is not very common, as it is frequent to include variable values calculated server side in inline scripts. And it means that your inline scripts change too frequently to manually add their hashes to your policy. This commonly happens when scripts are “localized”. WordPress has no API to implement nonces for CSP Even if it is easy to generate a nonce for each page view, this nonce has to be inserted in every script tag used to embed inline scripts in your page as doWhatever(); and in your script-src directive: script-src 'nonce-rAnd0m'; And, of course, a nonce must be unique for each HTTP response. Unsafe hashes / Inline styles Sometimes, HTML elements as images or buttons use HTML Event Attributes (onclick, onsubmit…) to let events trigger actions in a browser. You cannot use hashes or nonces for script included in event attributes and, adopting a strict CSP, requires refactoring those patterns into safer alternatives or to use ‘unsafe-hashes’. You got a similar problem when inline styles are used in HTML tags: This is a heading This is a paragraph. CSP Level 2 browsers may be ok with just putting the hash in your style-src directive. However, to allow hashes in the style attribute on inline CSS on browsers that support CSP Level 3, you may get an error like this Refused to apply inline style because it violates the following Content Security Policy directive: "style-src 'self' 'sha256-nMxMqdZhkHxz5vAuW/PAoLvECzzsmeAxD/BNwG15HuA='". Either the 'unsafe-inline' keyword, a hash ('sha256-nMxMqdZhkHxz5vAuW/PAoLvECzzsmeAxD/BNwG15HuA='), or a nonce ('nonce-...') is required to enable inline execution. To allow inline styles you need to use ‘unsafe-hashes’ in your style-src directive (that is, in facts, unsafe). ^ This plugin approach This plugin affords those problems in this way: During a capture phase, it detects the scripts, styles and other embedded content present in the pages of your site and stores them in the database. Then you have to whitelist these contents from plugin admin. The plugin uses machine learning to cluster inline scripts trying to aggregate scripts generated by the same server side (PHP) code. So, you can authorize one script example to authorize all scripts that the classifier predicts to label as whitelisted clusters. You can choose to use hashes to authorize external scripts (and the plugin will allow you to include Subresource Integrity in your and ) You can use hashes or nonces to authorize inline scripts. You can ask the plugin to refactor your page to not use event attributes (converted in a inline script) and inline styles (converted in an internal CSS). You can set one or more violations’ report endpoints. The plugin supports multisite installations and has (too) many options documented in inline help. Creating a Content Security Policy After plugin activation, go to Settings menu and search for CSP Settings submenu. The steps you are supposed to do are the following. From the Tools tab, activate the capture of the tags and use your site by visiting all the pages or having your users visit them for a long time long period based on the use of your site (hours or days). From the Tools tab, perform the data clustering in the database (it can use many server resources). Go to the Base rules tab and include in the CSP directives the desired values ​​(help you with the table at the bottom of the page). Go to the external scripts tab, inline scripts tab and scripts invoked by event handlers tab and authorize the execution of all the legitimate scripts present on the pages of your site. Leaving the tag capture active, activate the policy test (at this stage the plugin will generate some violations of the temporary policy used to record additional values to be included in the directives of your “content security policy”). After visiting again your site pages, disable the capture of the tags and repeat the previous steps 2, 3 and 4. Enable site protection. N.B. When you update plugins or themes, if something doesn’t work properly on your site pages, temporarily deactivate the protection and repeat steps 1 to 7. Plugin hooks Filters nunil_output_csp_headers_header_csp nunil_output_csp_headers_header_csp is available since version 1.2.3 and can be used to modify the Content-Security-Policy header before it is sent to browser no_unsafe_inline_not_sri_sources no_unsafe_inline_not_sri_sources can be used to modify the list of external resources that do not support SRI (Subresource Integrity) no_unsafe_inline_final_output no_unsafe_inline_final_output is an internal filter used to manipulate the output of the WordPress process just before the output is sent to the browser. no_unsafe_inline_meta_injector no_unsafe_inline_meta_injector is an internal filter hook used to inject meta http-equiv=”Content-Security-Policy” if variable is set Actions nunil_upgrade Functions hooked on nunil_upgrade will run when the plugin is upgraded nunil_output_csp_headers Functions hooked to nunil_output_csp_headers will run when the plugin output the CSP HTTP response header Code and libraries This version of the plugin uses: * to parse HTML: * ivopetkov/HTML5DOMDocument on PHP 2.13.09 * \Dom\HTMLDocument: The new ext-dom features with HTML5 support on PHP>8.4 * RubixML for machine learning from version 1.1.0 – PHP-ML was used in versions 1.0.x; * opctim/php-nilsimsa to calculate and compare Nilsimsa digests. The log functions have been taken from * perfectyorg/perfecty-push-wp, something you should really try if you want to implement web Push notifications in your site. The complete list of dependencies used in this plugin can be seen in dependency graph on GitHub. Contributions, Issues, Bugs Plugin code is hosted on a public repository on GitHub. Reach me over there to help and suggest.

The UpdraftPlus Backup & Migration Plugin is trusted by the WordPress community to backup, restore and migrate their WordPress websites. UpdraftPlus is actively installed on more than 3 million websites around the world. Backup with UpdraftPlus UpdraftPlus is the world’s highest ranking and most popular scheduled backup and migration plugin. Backup to your preferred storage location and restore in just three clicks. Backup to Dropbox, Google Drive, Amazon S3 (or compatible), Rackspace Cloud, FTP, DreamObjects, Openstack Swift or email. The paid version also allows you to backup to Microsoft OneDrive, Microsoft Azure, Google Cloud, Backblaze B2, SFTP, SCP, pCloud, WebDAV or UpdraftVault, our integrated storage option for UpdraftPlus. Backup manually or schedule to run every 2, 4, 8 or 12 hours, daily, weekly, monthly or fortnightly. Restore with UpdraftPlus Your WordPress website is vulnerable. Your site may get hacked. Something could go wrong with an update or your server could crash. You might need to reverse a change made or a mistake caused by human error. Whatever the reason, you can restore your WordPress website in just a few clicks with UpdraftPlus. Choose which components to restore (e.g. plugins, themes, database etc.), click again to restore, then click again to return to the main screen. Migrate with UpdraftPlus It’s easy to migrate your WordPress website to another web host, server or domain with this free version of UpdraftPlus. To migrate, simply download your database, plugins, themes etc. from the source site, then upload them into your destination site. When migrating, a built-in search-and-replace engine identifies old strings and replaces these to reflect the new location. UpdraftPlus saves you time and reduces the risk of broken links or missing files associated with manual migrations. Why UpdraftPlus? Writing a reliable backup and migration plugin that ‘just works’ consistently across millions of different WordPress deployments is hard. UpdraftPlus is relied upon to do exactly that. We’re trusted and actively deployed on more websites around the world than any other WordPress backup and migration plugin. UpdraftPlus: Backs up, migrates and restores Offers a huge number of remote storage locations Allows you to schedule backups, so you can ‘set and forget’ Is comprehensive and easy to use Is proven to work on over 3 million sites. UpdraftPlus Premium The free version of UpdraftPlus will back up and migrate your website perfectly well. However if you need more features and options you can purchase our Premium version. Backup and Migrate with UpdraftPlus Premium, and: Get automatic backups before updates. Restore the very latest version if a WordPress or plugin update breaks your site. Backup Incrementally. Changes are added to the master, saving server resources vs repeatedly backing up in full. Get more remote storage options including Microsoft OneDrive, SFTP, Microsoft Azure, WebDAV, Google Cloud, SCP, Backblaze and pCloud. Get 1GB of integrated storage with UpdraftVault for 99.999% reliability, redundancy and scalability. Get more control over how many backups are stored in a specified interval. Restore from other backup plugins including BackWPup, BackupWordPress, Simple Backups and more. Run backups at set times e.g. during periods of low traffic. Backup to more than one location for added protection. Get detailed reports. Includes cryptographic checksums so you can verify the integrity of the backup files and more. Get Premium migration. Migrating to the destination site is more direct and can be done from the source site. Get Multisite / multi-network compatibility. Backup non-WP files and databases e.g. tables belonging to your e-commerce store or customisations to WordPress core. Get database encryption. Manage your backups and migrations from the WP-CLI. Get Premium Support. Find out more on our comparison page. UpdraftPlus Premium is available for purchase here. Managing multiple websites? UpdraftCentral is a powerful remote control dashboard for WordPress that allows you to manage your backups, as well as updates, users, pages, posts, plugins and themes from one central location. Choose between: UpdraftCentral (free, self-hosted) UpdraftCentral Premium (paid-for, self-hosted) UpdraftCentral Cloud (paid-for, fully-hosted) Optimize your sites centrally by combining the power of WP-Optimize and UpdraftCentral or manage your backups centrally by combining the power of UpdraftPlus with UpdraftCentral. Need to create a temporary clone of your site? UpdraftClone makes it quick and easy to create a temporary sandbox for changes you want to try out. Simply select the versions of WordPress and PHP that you want, and we’ll do the rest. More about UpdraftClone The full suite of plugins from Team Updraft and friends UpdraftPlus. Backup, migrate and restore. Rated 5* on the plugin directory and trusted by more than 3 million WordPress website owner WP-Optimize. Clean the database, compress images and caching. Optimize your WordPress website. 5* user rating. 1 million + active installs. All-In-One Security (AIOS). Secure your WordPress website. Comprehensive, feature rich and easy to use. 5* user rating and 1 million + active installs. WP Overnight. Quality Extensions for your WooCommerce store. 5* rated invoicing, order and product management, customer management solutions and more. Easy Updates Manager. Take control of updates. Lots of features for free, and a Premium version with even more – over 300,000 users. Internal Link Juicer.Boost your SEO. Automate internal links within your WordPress website. Save time and rank higher in the search engines. For other useful, free plugins see our lead developer’s profile, here. Are you multilingual? Can you translate? Do you want to help people that speak your language to backup, migrate and restore their WordPress websites? The UpdraftPlus backup, migration and restoration plugin is ready and waiting. The translation process is easy, and web-based – please go here for instructions: https://updraftplus.com/translate/. Or, if you’re already an expert WordPress translator, just pick out the .pot file from the wp-content/plugins/updraftplus/languages/ directory – if you scan for translatable strings manually, then you need to get these functions: _x(), __(), _e(), _ex(), log_e(). Many thanks to our existing translators. License Copyright 2011-24 David Anderson This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Non-English translators are provided by volunteers, and wordpress.org does not give plugin developers control over their translations; thus relying on them is at your own risk; UpdraftPlus cannot guarantee that translations from the original English are accurate. We recognise and thank those mentioned at https://updraftplus.com/acknowledgements/ for code and/or libraries used and/or modified under the terms of their open source licences.