Security Best Practices for Drupal: Safeguarding Your Website

When building and managing a Drupal website, security must always be a top priority. Drupal is known for its robust security features, but no system is immune to vulnerabilities. Following best practices is essential to ensure that your website remains secure against various types of attacks, from malicious users to automated bots. This blog post will outline key security best practices for Drupal, helping you create a more secure environment for your content, users, and data.

In this article, we’ll cover the following Drupal security best practices:

Update Core & Modules: Regularly update Drupal core and contributed modules to protect against known vulnerabilities.
Role & Permissions Management: Follow the principle of least privilege by limiting user roles and permissions to reduce the attack surface.
Sanitize Inputs: Always validate and sanitize user inputs when developing custom code to avoid common vulnerabilities like cross-site scripting (XSS) and SQL injection.
Secure Configuration: Ensure proper security configurations, such as HTTPS, password policies, and user authentication settings.

Let’s dive into each of these best practices in detail, and learn how you can implement them to strengthen the security of your Drupal site.

1. Update Drupal Core & Contributed Modules

Keeping your Drupal installation and contributed modules up to date is one of the most important steps in maintaining a secure website. Security vulnerabilities are discovered regularly, and when they are, the Drupal Security Team and module maintainers release patches and updates to address them. Failing to apply these updates leaves your site exposed to potential attacks.

Why Updating is Critical

Outdated software is one of the most common vectors for cyberattacks. Hackers are constantly scanning for websites running vulnerable versions of software, and once a vulnerability is publicly disclosed, attackers can exploit it to gain access to your site, inject malicious code, or steal sensitive data.

Drupal core and module updates are not just about new features; they often include critical security patches that address known vulnerabilities. If you delay updates, your site remains open to these threats.

How to Stay Up to Date

Monitor Security Advisories: Regularly check the Drupal Security Advisories page for updates on core and contributed modules. Subscribe to the newsletter to stay informed about important security releases.
Use Composer: If you're using Composer to manage your Drupal site, updating modules and core is simple. Use the following commands to check for updates and apply them:

   composer outdated "drupal/*"
   composer update drupal/core --with-dependencies

Automated Updates (Future Feature): Keep an eye on the upcoming Drupal 10 feature for automated updates, which will help ensure that critical security patches are applied automatically.
Backup Before Updating: Always backup your site and database before applying updates, especially when updating Drupal core or key contributed modules.

2. Role & Permissions: Follow the Principle of Least Privilege

One of the foundational principles of security is the principle of least privilege. This means that users should have the minimum amount of access necessary to perform their tasks. The more permissions a user has, the larger the attack surface of your website. By limiting access, you reduce the potential damage that can be caused by compromised accounts or malicious users.

Why Role & Permission Management Matters

Misconfigured roles and permissions are a common cause of security breaches. For example, if a user has unnecessary administrative permissions, a compromised account could give an attacker full control of the site. Limiting permissions helps contain potential security issues and minimizes the risk of a successful attack.

How to Implement Least Privilege in Drupal

Audit Roles and Permissions: Regularly review all user roles and permissions to ensure that they are properly configured. Drupal provides a granular permission system that allows you to control exactly what each role can do. Limit access to sensitive areas of the site, such as the admin dashboard, content editing, and configuration settings.
Limit Administrative Access: Only grant administrative permissions to trusted users who need them. For example, avoid giving "Administrator" permissions to regular content editors or contributors.
Use Custom Roles: Instead of giving broad permissions to a few predefined roles, create custom roles tailored to the specific needs of your users. For example, create a “Content Editor” role with just the permissions necessary to create and edit content, without access to site configuration.
Use Two-Factor Authentication (2FA): For users with administrative or other elevated privileges, require two-factor authentication (2FA) to add an additional layer of security. The TFA module for Drupal can help you implement 2FA.

Example: Limiting Permissions for Content Editors

When creating a custom role for content editors, you might want to limit their permissions to the following:

Create and edit their own content
Edit published content
Access content overview pages
Avoid giving access to configuration pages, the admin toolbar, or permissions management

By carefully assigning permissions, you can reduce the risk of unintentional or malicious damage to your site.

3. Sanitize Inputs: Validating and Sanitizing User Inputs

When developing custom code or modules, one of the most critical security measures is to validate and sanitize any user inputs. Failure to do so can open your site to common vulnerabilities like cross-site scripting (XSS), SQL injection, and cross-site request forgery (CSRF).

Why Input Sanitization is Important

User input is one of the most common attack vectors for hackers. By injecting malicious code into form fields, URLs, or other input points, attackers can exploit vulnerabilities to gain control of your site, steal data, or execute malicious actions.

For example, XSS attacks occur when an attacker injects malicious JavaScript into a page that is then rendered by the browser. SQL injection occurs when user input is improperly handled and inserted directly into SQL queries, allowing the attacker to manipulate the database.

How to Sanitize User Inputs in Drupal

Use Drupal’s APIs: Drupal provides built-in APIs to handle input sanitization and validation. For example, the Filter API can be used to sanitize HTML input, and the Database API automatically handles SQL injection prevention.
Always Escape Output: When displaying user-generated content, always use the t() function or the Twig |escape filter to escape output and prevent XSS attacks.

   echo t('Hello, @name!', ['@name' => $user_input]);

Validate Inputs: When building forms, use Drupal’s Form API to validate user inputs. This ensures that only valid data is accepted. For example, use the #element_validate property to validate form elements before submission.

   $form['email'] = [
     '#type' => 'email',
     '#title' => t('Email address'),
     '#required' => TRUE,
     '#element_validate' => ['my_custom_email_validation_function'],
   ];

Limit Allowed HTML: When allowing users to submit HTML content (e.g., in a rich text editor), configure a text format that only allows safe HTML tags and attributes. Use the Text Formats section in Drupal to define what is allowed.
Use CSRF Tokens: When building custom forms or actions, always use CSRF tokens to protect against cross-site request forgery attacks. Drupal’s Form API automatically handles CSRF protection, but you can manually add tokens to custom routes if necessary.

4. Secure Configuration: Locking Down Your Drupal Installation

Ensuring that your Drupal installation is properly configured is essential for security. There are several configuration settings and tools that you should enable to secure your site against unauthorized access and data breaches.

Important Security Configurations in Drupal

Use HTTPS: Always serve your Drupal site over HTTPS to protect data in transit. SSL/TLS encryption ensures that sensitive information, such as login credentials or payment data, is securely transmitted between the user’s browser and your server.
Secure Password Policies: Set up strong password policies to ensure that users create secure passwords. Use the Password Policy module to enforce rules like minimum password length, complexity, and password expiration.
Limit Login Attempts: Use the Login Security module to limit the number of failed login attempts and block IP addresses after too many failed attempts. This protects your site against brute-force attacks.
Disable Unused Modules: Disable and uninstall any modules that are not being used. Unnecessary modules can introduce vulnerabilities or increase the attack surface of your site.
Review File Permissions: Ensure that the file permissions on your Drupal installation are properly configured. Only allow write access to directories that need it (e.g., sites/default/files), and ensure that sensitive files (e.g., settings.php) are read-only.
Use Security Headers: Configure your web server to include security headers like Content Security Policy (CSP), X-Frame-Options, and X-Content-Type-Options. These headers help protect against various attacks, such as XSS and clickjacking.

Enabling Trusted Host Settings

To protect against HTTP Host header attacks, configure Trusted Host Settings in settings.php:

$settings['trusted_host_patterns'] = [
  '^www\.example\.com$',
  '^example\.com$',
];

This ensures that Drupal only serves requests from authorized domains, preventing attackers from tricking your site into serving content on unauthorized domains.

Conclusion

Security is a continuous process, and following these best practices can help protect your Drupal website from the most common vulnerabilities and attacks. By regularly updating Drupal core and contributed

modules, carefully managing roles and permissions, sanitizing user inputs, and ensuring secure configurations, you significantly reduce the risk of a security breach.

Remember, security is not just a developer’s responsibility—it’s a team effort. Make sure your entire team is aware of these best practices and integrates them into the development and maintenance workflow.

By following these security best practices, you can build a resilient, secure Drupal site that protects both your data and your users, ensuring long-term success and trustworthiness.

Security Best Practices