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Threat Model Analysis for bookstackapp/bookstack

Threat: LDAP Authentication Bypass

  • Description: An attacker crafts malicious LDAP responses to bypass authentication or gain elevated privileges. They might exploit a lack of proper validation of LDAP attributes returned by the server, or manipulate the LDAP search filter used by BookStack. For example, they could inject LDAP syntax to alter the query and return a positive result even with incorrect credentials, or to return attributes that grant them administrator privileges.
  • Impact: Unauthorized access to the BookStack instance, potentially with administrator privileges, leading to complete data compromise, modification, or deletion.
  • Affected Component: app/Auth/Access/LdapService.php (and related LDAP configuration settings). Specifically, the functions responsible for connecting to the LDAP server, performing searches, and validating user attributes.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer:
      • Implement strict validation of all data received from the LDAP server, including user attributes and search results. Do not trust any data from the LDAP server without thorough sanitization and validation.
      • Use parameterized queries or LDAP libraries that prevent LDAP injection vulnerabilities. Avoid constructing LDAP search filters by directly concatenating user input.
      • Implement robust error handling for LDAP connection and query failures.
      • Regularly review and update the LDAP library used by BookStack.
    • User:
      • Ensure the LDAP server is properly configured and secured.
      • Use a dedicated service account for BookStack's LDAP connection, with the minimum necessary permissions.
      • Monitor LDAP server logs for suspicious activity.
      • Enable TLS/SSL for the LDAP connection.

Threat: OAuth Account Hijacking

  • Description: An attacker exploits vulnerabilities in BookStack's OAuth flow to link their malicious account to a legitimate BookStack user's account. This could involve manipulating the redirect URI, state parameter, or other aspects of the OAuth handshake. For example, they might intercept the authorization code and use it to link their own social media account to a victim's BookStack account.
  • Impact: Unauthorized access to the victim's BookStack account, potentially leading to data compromise, modification, or deletion.
  • Affected Component: app/Auth/Access/RegistrationService.php, app/Auth/Access/SocialAuthService.php (and related OAuth configuration settings). Specifically, the functions handling the OAuth authorization flow, including redirect URI validation, state parameter handling, and token exchange.
  • Risk Severity: High
  • Mitigation Strategies:
    • Developer:
      • Strictly validate the redirect URI against a whitelist of allowed URLs.
      • Use a cryptographically secure random number generator to generate the state parameter and verify it upon return.
      • Implement robust error handling for OAuth failures.
      • Regularly review and update the OAuth library used by BookStack.
      • Ensure that the OAuth provider's API is used securely, following best practices.
    • User:
      • Use strong passwords for their social media accounts.
      • Be cautious when granting permissions to applications.
      • Monitor their social media account activity for suspicious logins.

Threat: Permission Bypass for Content Modification

  • Description: A user with "view-only" permissions exploits a logic flaw in BookStack's permission system to modify content (pages, chapters, books, or attachments). This could involve manipulating request parameters, bypassing client-side checks, or exploiting inconsistencies in how permissions are enforced across different parts of the application. For example, a user might find an API endpoint that doesn't properly check permissions, allowing them to directly modify page content.
  • Impact: Unauthorized modification of content, leading to data corruption, misinformation, or defacement.
  • Affected Component: app/Entities/, specifically files related to models (e.g., Page.php, Chapter.php, Book.php) and their respective controllers (e.g., PageController.php, ChapterController.php, BookController.php). The core permission checking logic, likely within app/Auth/Permissions/PermissionService.php and related classes, is also a key component.
  • Risk Severity: High
  • Mitigation Strategies:
    • Developer:
      • Implement server-side permission checks for all actions that modify content, regardless of client-side checks. Do not rely solely on client-side validation.
      • Use a consistent and centralized permission checking mechanism throughout the application.
      • Thoroughly test all permission-related functionality, including edge cases and boundary conditions.
      • Regularly review and audit the permission system code.
      • Ensure that API endpoints enforce the same permission checks as the web interface.
    • User:
      • Regularly review user roles and permissions to ensure they are appropriate.
      • Monitor audit logs for suspicious activity.

Threat: Attachment Storage Manipulation

  • Description: An attacker uploads a malicious file that bypasses BookStack's file type or size restrictions, or exploits vulnerabilities in how BookStack stores or processes attachments. This could involve uploading a file with a manipulated extension, a file containing malicious code (e.g., a PHP script disguised as an image), or a file that triggers a vulnerability in an image processing library used by BookStack. The attacker might then be able to execute arbitrary code on the server, delete other attachments, or access restricted files.
  • Impact: Server compromise, data loss, or unauthorized access to files.
  • Affected Component: app/Uploads/ directory and related classes (e.g., AttachmentService.php, ImageService.php, ImageManager.php). Specifically, the functions responsible for handling file uploads, validating file types and sizes, storing files, and processing images.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer:
      • Implement strict server-side validation of all uploaded files, including file type, size, and content. Do not rely solely on client-side checks or file extensions.
      • Store uploaded files outside the web root, or configure the web server to prevent direct access to the attachments directory.
      • Use a secure file naming scheme to prevent directory traversal attacks.
      • Regularly update any image processing libraries used by BookStack.
      • Consider using a separate service or server for handling attachments.
      • Scan uploaded files for malware.
    • User:
      • Be cautious when uploading files from untrusted sources.
      • Monitor server logs for suspicious activity.