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Mitigation Strategies Analysis for drupal/core

Mitigation Strategy: Keep Drupal Core Up-to-Date

Description: 1. Establish an Update Schedule: Define a regular schedule for checking and applying Drupal core updates (e.g., monthly, or immediately for security releases). 2. Subscribe to Security Advisories: Subscribe to Drupal security mailing lists ([email protected]) and utilize platforms like Drupal.org's security advisory page to receive notifications about Drupal core security releases. 3. Utilize Core Update Tools: Employ tools like Drush (drush updb, drush core-update) or Drupal Console (drupal update:entities, drupal core:update) to streamline the core update process. These tools automate downloading and applying core patches. 4. Backup Before Updating Core: Always create a full database and files backup before applying any Drupal core updates. This allows for easy rollback in case of issues during the core update process. 5. Test Core Updates in a Staging Environment: Apply core updates to a staging environment that mirrors the production environment. Thoroughly test core functionality and look for regressions before deploying the core update to production. 6. Prioritize Core Security Updates: Treat Drupal core security updates with the highest priority. Apply them as soon as possible, ideally within hours or days of release, especially for critical core vulnerabilities. 7. Monitor Core Update Status: Regularly check the Drupal admin interface's "Available updates" page or use Drush/Drupal Console commands to monitor the status of Drupal core and identify available core updates.

  • Threats Mitigated:
    • Exploitation of Known Drupal Core Vulnerabilities (High Severity): Outdated Drupal core versions are susceptible to publicly known vulnerabilities that attackers can easily exploit. This can lead to data breaches, website defacement, and complete site compromise specifically through core weaknesses.
    • Remote Code Execution (RCE) in Drupal Core (Critical Severity): Some Drupal core vulnerabilities can allow attackers to execute arbitrary code on the server, granting them full control over the application and server due to flaws in core.
    • Cross-Site Scripting (XSS) in Drupal Core (Medium to High Severity): Outdated core versions may contain XSS vulnerabilities within Drupal core itself, allowing attackers to inject malicious scripts into the website via core functionalities.
    • SQL Injection in Drupal Core (Medium to High Severity): Although less common, outdated Drupal core might have SQL injection vulnerabilities that could allow attackers to access or modify the database through core database interactions.
    • Denial of Service (DoS) via Drupal Core (Medium Severity): Some vulnerabilities in older core versions can be exploited to cause denial of service, making the website unavailable due to core processing issues.
  • Impact: High. Regularly updating Drupal core is the most crucial mitigation strategy for core-related vulnerabilities. It directly addresses the root cause of many Drupal-specific vulnerabilities originating from core code by patching them. This significantly reduces the risk of exploitation of core weaknesses.
  • Currently Implemented: Partially implemented. Most projects likely have some form of Drupal core update process, but the frequency and rigor may vary. Many projects use Drush or Drupal Console for core updates. Subscribing to security advisories is a best practice, but might not be consistently followed for core specifically. Staging environments are common but not universal for core updates.
  • Missing Implementation: Consistent and timely application of Drupal core updates, especially security updates, is often missing. Automated testing after core updates and a clearly defined and enforced core update schedule are frequently lacking. Proactive monitoring of Drupal core security advisories and immediate action upon critical core releases could be improved in many projects.

Mitigation Strategy: Leverage Drupal's Built-in Core Security Features

Description: 1. Core Permissions System: * Principle of Least Privilege in Core Permissions: Grant users only the minimum necessary core permissions to perform their tasks within Drupal's core functionalities. Avoid assigning powerful core roles like "administrator" unnecessarily. * Role-Based Access Control (RBAC) using Core Roles: Define clear roles (e.g., editor, author, contributor) using Drupal core's role system and assign core permissions to these roles, not individual users. * Regular Core Permission Audits: Periodically review user roles and core permissions to ensure they are still appropriate and remove any unnecessary core privileges. 2. Core Form API and CSRF Protection: * Always Use Drupal Core Form API: Construct all forms, especially those interacting with core functionalities, using Drupal's Form API. This automatically includes core CSRF protection tokens in forms. * Avoid Bypassing Core Form API: Do not bypass the core Form API and create forms directly in HTML or using other methods, as this will likely miss core CSRF protection. 3. Core Database Abstraction Layer: * Use \Drupal::database() Core API: Access the database exclusively through Drupal's core database API (\Drupal::database()) for all database interactions, including those related to core data. * Prepared Statements with Placeholders in Core Queries: Use prepared statements and placeholders for all database queries involving user input, especially when interacting with core database tables. This prevents SQL injection in core database operations. 4. Core Rendering System and Twig Auto-escaping: * Utilize Core Twig Templating: Use Twig as the templating engine for all themes and modules, relying on Drupal core's rendering system. Twig provides automatic output escaping by default within the core rendering context. * Understand Core Auto-escaping Contexts: Be aware of Twig's auto-escaping contexts (HTML, JavaScript, CSS, URL) within Drupal core and how they protect against XSS in different situations when rendering core data. 5. Core Content Access Control: * Configure Core Content Access: Utilize Drupal core's content access control features (e.g., node access settings, taxonomy access control) to restrict access to content managed by core, based on user roles and permissions defined within core.

  • Threats Mitigated:
    • Unauthorized Access to Core Functionality (Medium to High Severity): Improperly configured core permissions and access control can lead to unauthorized users accessing sensitive core data or functionalities.
    • Cross-Site Request Forgery (CSRF) in Core Forms (Medium Severity): Lack of CSRF protection in forms interacting with core can allow attackers to perform actions on behalf of authenticated users within core functionalities without their knowledge.
    • SQL Injection in Core Database Interactions (High Severity): Failure to use prepared statements and proper core database API usage can lead to SQL injection vulnerabilities in core database operations, allowing attackers to manipulate core database queries.
    • Cross-Site Scripting (XSS) via Core Rendering (Medium to High Severity): Improper output escaping and bypassing Twig's auto-escaping in core rendering contexts can lead to XSS vulnerabilities, allowing attackers to inject malicious scripts through core rendered output.
  • Impact: High. Leveraging Drupal core's built-in security features is fundamental to building a secure Drupal application based on core. These core features are designed to address common web application vulnerabilities and provide a strong security foundation within the core framework. Proper utilization significantly reduces the risk of these core-related threats.
  • Currently Implemented: Partially implemented. Drupal core inherently includes these features, but their effective implementation depends on developer practices and configuration within the core context. Core Form API and core database abstraction are generally well-used. Core Twig auto-escaping is default. Core permissions system is used, but granularity and regular audits of core permissions might be lacking. Core content access control is often implemented but can be complex and require careful core configuration.
  • Missing Implementation: Consistent and thorough application of the principle of least privilege in core permissions, regular audits of core permissions, and careful consideration of core content access control requirements are often missing. Developers might sometimes bypass core Form API or core database abstraction in custom code interacting with core, introducing vulnerabilities. Understanding and correctly utilizing core Twig's auto-escaping and manual escaping when necessary within core rendering contexts requires developer awareness and training related to core functionalities.

Mitigation Strategy: Secure Drupal Core Configuration

Description: 1. Disable Unnecessary Core Modules: * Identify Unused Core Modules: Regularly review the list of enabled Drupal core modules and identify those that are not actively used or essential for the website's core functionality. * Disable and Uninstall Unused Core Modules: Disable and then uninstall unused core modules to reduce the attack surface and potential vulnerabilities associated with them within Drupal core. * Regular Core Module Review: Make this a part of routine maintenance to ensure only necessary core modules are enabled. 2. Restrict Core File Permissions: * Follow Drupal Core Recommendations: Adhere to Drupal's recommended file permissions guidelines for core directories and files. These guidelines typically involve setting web server user ownership and restricting write access to specific core directories. * Regularly Verify Core Permissions: Periodically check file permissions for core files and directories to ensure they haven't been inadvertently changed or misconfigured, especially after core updates or deployments. 3. Secure settings.php (Core Configuration File): * Restrict Access to settings.php: Set file permissions for settings.php to be readable only by the web server user and the user performing deployments. Prevent public access to this core configuration file. * Secure Database Credentials in settings.php: Ensure database credentials in settings.php are strong and securely stored. Avoid default or easily guessable passwords for the database used by Drupal core. * Limit Access to Core Database: Restrict database user access to only the necessary privileges and from allowed IP addresses if possible, for the database used by Drupal core. 4. Configure Core Error Reporting: * Log Core Errors: Configure Drupal core to log errors to the watchdog log or a separate log file. This is crucial for debugging core issues and security monitoring of core functionalities. * Disable Displaying Core Errors in Production: In production environments, disable displaying core errors to end-users. This prevents information disclosure about Drupal core's internal workings. Set error reporting to "Errors and warnings to the log" or "None" for core in production. 5. Disable Debugging and Development Core Modules in Production: * Identify Development Core Modules: Recognize core modules intended primarily for development and debugging purposes (if any exist and are enabled). * Disable Development Core Modules in Production: Ensure these core modules are completely disabled in production environments. They can expose sensitive core information, introduce performance overhead within core, and create security vulnerabilities related to core debugging features.

  • Threats Mitigated:
    • Information Disclosure via Core Configuration (Medium Severity): Misconfigured core error reporting and enabled development core modules in production can expose sensitive information about Drupal core, server paths, and internal workings to attackers.
    • Unauthorized Access due to Core Configuration (Medium Severity): Weak file permissions for core files and insecure settings.php configuration can allow unauthorized users to access sensitive core files or modify the Drupal core installation.
    • Privilege Escalation via Core Misconfiguration (Medium Severity): Incorrect file permissions for core files or misconfigured core modules could potentially be exploited for privilege escalation within the Drupal core system.
    • Denial of Service (DoS) via Core Modules (Low Severity): Enabled development core modules in production can sometimes introduce performance overhead within core, potentially contributing to DoS vulnerabilities under heavy load on core functionalities.
  • Impact: Medium. Secure Drupal core configuration is essential for hardening the Drupal core application. It reduces the attack surface within core, prevents information leakage related to core, and mitigates various configuration-related vulnerabilities stemming from core settings. While not directly patching code vulnerabilities in core, it strengthens the overall security posture of the Drupal core installation.
  • Currently Implemented: Partially implemented. Disabling error display in production is generally a standard practice for Drupal core. File permissions for core files are often set during initial setup but might not be regularly reviewed. Securing settings.php is usually considered for core, but the level of security might vary. Disabling development modules in production is a known best practice for Drupal core, but might be overlooked. Regular review of core security settings is less common.
  • Missing Implementation: Regular reviews of enabled Drupal core modules and disabling unused ones are often missed. Consistent adherence to Drupal's recommended file permissions for core files and periodic verification are lacking. Proactive review of all security-related core configuration settings and establishing a process for maintaining secure core configuration over time are often missing.

Mitigation Strategy: Secure Drupal Core File Upload Handling

Description: 1. Restrict File Types in Drupal Core: * Whitelist Allowed Extensions in Core: Define a strict whitelist of allowed file extensions for file uploads handled by Drupal core. Only permit necessary file types and reject all others within core's file upload mechanisms. * Validate File Extension in Core: Validate the file extension on the server-side after upload, specifically for file uploads processed by Drupal core. Do not rely solely on client-side validation, which can be bypassed, for core file uploads. 2. Validate File Content in Drupal Core: * MIME Type Validation in Core: Check the MIME type of the uploaded file to verify it matches the expected file type, specifically for core file uploads. However, MIME types can be spoofed, so this should not be the sole validation method for core. * File Header Validation (Magic Bytes) in Core: Validate the file header (magic bytes) to further confirm the file type for core file uploads. This is a more reliable method than MIME type validation for core. 3. File Size Limits in Drupal Core: * Implement File Size Limits in Core: Enforce file size limits for file uploads handled by Drupal core to prevent denial-of-service attacks through large file uploads and to manage storage space used by core. * Configure Limits in Drupal Core Settings: Configure file size limits within Drupal core's file upload settings. 4. Secure Storage Location for Drupal Core Uploads: * Store Core Uploads Outside Webroot (If Possible): Store uploaded files handled by Drupal core outside of the webroot directory if possible. This prevents direct execution of uploaded files as scripts within the core context. * Random Filenames for Core Uploads: Generate random and unpredictable filenames for uploaded files handled by Drupal core to prevent filename guessing and directory traversal attacks related to core uploads. * Directory Indexing Disabled for Core Uploads: Ensure directory indexing is disabled for the upload directory used by Drupal core to prevent attackers from listing directory contents of core upload directories. 5. Access Control for Drupal Core Uploaded Files: * Restrict Access to Core Uploads: Implement access control mechanisms to restrict access to uploaded files handled by Drupal core to authorized users only, using Drupal core's permission system. * Drupal Core's Private File System: Utilize Drupal core's private file system for sensitive uploads handled by core and configure appropriate access permissions within core. 6. Sanitize Filenames for Drupal Core Uploads: * Remove Special Characters in Core Filenames: Sanitize filenames for core uploads by removing or replacing special characters, spaces, and potentially harmful characters that could be used for directory traversal or other attacks related to core file handling. * Limit Filename Length for Core Uploads: Enforce filename length limits for core uploads to prevent buffer overflow vulnerabilities or issues with file system limitations within core file handling. 7. Regular Security Review of Core Upload Functionality: * Periodic Review of Core Uploads: Regularly review the file upload functionality and security configurations within Drupal core to ensure they remain effective and are updated as needed for core file handling.

  • Threats Mitigated:
    • Remote Code Execution (RCE) via Drupal Core File Uploads (Critical Severity): Unrestricted file uploads handled by Drupal core, especially of executable file types (e.g., PHP, scripts), can allow attackers to upload and execute malicious code on the server through core functionalities, leading to complete site compromise via core weaknesses.
    • Cross-Site Scripting (XSS) via Drupal Core File Uploads (Medium to High Severity): Uploading files containing malicious scripts (e.g., HTML, SVG with JavaScript) through Drupal core's file upload mechanisms can lead to stored XSS vulnerabilities if these files are served directly or their content is displayed without proper sanitization by core.
    • Directory Traversal via Drupal Core File Uploads (Medium Severity): Improper filename sanitization in Drupal core file handling can allow attackers to use directory traversal techniques to upload files outside of the intended upload directory via core functionalities, potentially overwriting system files or accessing sensitive data through core file operations.
    • Denial of Service (DoS) via Drupal Core File Uploads (Medium Severity): Allowing excessively large file uploads through Drupal core's mechanisms can lead to DoS attacks by consuming server resources (disk space, bandwidth) due to core file processing.
    • Malware Uploads via Drupal Core (Variable Severity): Unvalidated file uploads through Drupal core can allow users to upload malware or viruses, potentially infecting the server or other users who download the files via core file sharing features.
  • Impact: High. Secure Drupal core file uploads are critical to prevent a range of severe vulnerabilities originating from core file handling. Improperly secured core file uploads are a common entry point for attackers to compromise web applications through core weaknesses. Implementing robust file upload security measures within Drupal core significantly reduces the risk of these core-related threats.
  • Currently Implemented: Partially implemented within Drupal core. File type restrictions (whitelisting extensions) are often implemented in Drupal core's file handling, but the level of strictness and completeness can vary. File size limits are usually configured in core. Storing files outside the webroot for core uploads is less common, especially for simpler Drupal setups. Filename sanitization and access control for uploaded files via core are often overlooked or not implemented comprehensively in core configurations. Virus scanning is rarely integrated directly into Drupal core's file upload process.
  • Missing Implementation: Comprehensive file content validation (beyond MIME type) for Drupal core uploads, storing core uploads outside the webroot, robust filename sanitization for core uploads, granular access control for files uploaded via core, and integration of virus scanning into Drupal core's file upload handling are often missing. Regular security reviews of Drupal core's file upload functionality are also not consistently performed.