mitigations.md

Mitigation Strategies Analysis for naptha/tesseract.js

Mitigation Strategy: Validate Image File Types

1. Validate Image File Types

• Mitigation Strategy: Validate Image File Types
• Description:
  1. Define Allowed Types: Strictly define and enforce a whitelist of image file types that tesseract.js is expected to process correctly and securely (e.g., PNG, JPEG, TIFF).
  2. Client-Side Validation (Optional): Implement client-side JavaScript checks to verify the file extension or MIME type of uploaded images before they are processed by tesseract.js. This provides immediate feedback and reduces unnecessary processing.
  3. Server-Side Validation (Mandatory): Perform robust server-side validation. Before passing the image data to tesseract.js (if server-side processing is involved in your architecture), verify the file type using server-side libraries that can inspect file headers or magic numbers. Reject any files that do not conform to the allowed types. This prevents tesseract.js from attempting to process unexpected or potentially malicious file formats.
• List of Threats Mitigated:
  • Malicious File Processing Exploits (High Severity): Prevents tesseract.js or underlying image decoding libraries from attempting to process file types that could trigger vulnerabilities due to unexpected file structures or malicious content embedded within non-image file types disguised as images.
  • Unexpected tesseract.js Behavior (Medium Severity): Reduces the risk of tesseract.js encountering errors or producing unreliable results when given file types it's not designed to handle, leading to application instability or incorrect OCR output.
• Impact:
  • Malicious File Processing Exploits: High risk reduction. Significantly reduces the attack surface related to file type manipulation and potential exploits within tesseract.js's image processing pipeline.
  • Unexpected tesseract.js Behavior: Medium risk reduction. Improves the stability and predictability of tesseract.js operations.
• Currently Implemented: Partially implemented. Client-side validation based on file extension is present in the image upload component.
• Missing Implementation: Server-side validation using magic number inspection is missing. Server-side Content-Type header validation is also not consistently enforced before images are processed by tesseract.js (if server-side processing is used).

Mitigation Strategy: Image Content Validation (Relevant to OCR Processing)

2. Image Content Validation (Relevant to OCR Processing)

• Mitigation Strategy: Image Content Validation (Relevant to OCR Processing)
• Description:
  1. Dimension Checks (Pre-OCR): Before feeding the image to tesseract.js, perform checks on image dimensions (width and height). Set reasonable maximum limits to prevent tesseract.js from processing excessively large images that could lead to performance issues or resource exhaustion within the tesseract.js processing.
  2. Basic Image Integrity Checks (Pre-OCR): Use client-side or server-side image processing capabilities (if available before tesseract.js processing) to perform basic integrity checks. This could include attempting to decode the image to ensure it's not corrupted or malformed before passing it to tesseract.js.
• List of Threats Mitigated:
  • Denial of Service (DoS) via tesseract.js Resource Exhaustion (Medium Severity): Prevents tesseract.js from being forced to process extremely large or complex images that could consume excessive client-side or server-side resources (CPU, memory, processing time) during the OCR process itself.
  • tesseract.js Processing Errors (Low to Medium Severity): Reduces the likelihood of tesseract.js encountering errors or producing unreliable results when processing images with characteristics that might be problematic for the OCR engine (e.g., extremely large dimensions, corrupted image data that might still be valid file types).
• Impact:
  • Denial of Service (DoS) via tesseract.js: Medium risk reduction. Reduces the impact of DoS attacks that target tesseract.js processing resources directly.
  • tesseract.js Processing Errors: Medium risk reduction. Improves the robustness and reliability of tesseract.js results.
• Currently Implemented: No image content validation beyond file type is currently implemented specifically before tesseract.js processing.
• Missing Implementation: Implementation of dimension checks and basic integrity checks before passing images to tesseract.js is missing.

Mitigation Strategy: Sanitize Input to tesseract.js Configuration

3. Sanitize Input to tesseract.js Configuration

• Mitigation Strategy: Sanitize Input to tesseract.js Configuration
• Description:
  1. Parameter Whitelisting: Strictly whitelist the configuration options that can be passed to tesseract.js. Only allow parameters that are absolutely necessary for the application's OCR functionality and are considered safe.
  2. Input Validation for Configuration Values: If any configuration values are derived from user input (which should be minimized for security), rigorously validate and sanitize these values before passing them to tesseract.js. Ensure they conform to expected types, formats, and ranges.
  3. Avoid Dynamic Configuration Construction: Avoid dynamically constructing tesseract.js configuration strings or objects based on unsanitized user input. Prefer using predefined configuration templates or safe parameter passing methods provided by the tesseract.js API.
• List of Threats Mitigated:
  • tesseract.js Configuration Injection Vulnerabilities (Potentially High Severity, Context Dependent): If tesseract.js or its underlying components have vulnerabilities in how they parse or process configuration options, unsanitized user input injected into configuration could potentially lead to unexpected behavior, code injection, or other security issues within the tesseract.js execution context. The severity depends on the specific vulnerabilities and how configuration is handled by tesseract.js.
• Impact:
  • tesseract.js Configuration Injection Vulnerabilities: Medium to High risk reduction. Significantly reduces the attack surface by limiting and sanitizing configuration input to tesseract.js.
• Currently Implemented: Configuration for tesseract.js is mostly hardcoded. Language selection is parameterized but uses a dropdown with predefined options, effectively whitelisting input.
• Missing Implementation: While currently safe due to hardcoded configuration and whitelisting, there's no explicit input sanitization or validation applied to the language parameter in the code. If more configuration options are exposed to user input in the future, robust sanitization will be crucial.

Mitigation Strategy: Treat OCR Output as Untrusted User Input

4. Treat OCR Output as Untrusted User Input

• Mitigation Strategy: Treat OCR Output as Untrusted User Input
• Description:
  1. Identify Output Usage Points: Locate every instance in the application's code where the text output generated by tesseract.js is used. This includes displaying it in the user interface, using it in JavaScript logic, or storing it for later use.
  2. Contextual Sanitization: For each usage point, apply appropriate output sanitization techniques specifically designed to prevent vulnerabilities related to displaying or processing untrusted text. This is crucial because OCR output could contain malicious content if the input image was crafted to inject it.
     • HTML Display: Use HTML escaping functions to prevent Cross-Site Scripting (XSS) when displaying OCR output in HTML content.
     • JavaScript String Operations: Use JavaScript string escaping or other appropriate methods if the output is used in JavaScript code to prevent injection vulnerabilities in dynamic code execution or string manipulation.
     • Database Storage: Sanitize or encode data before storing it in the database to prevent potential injection vulnerabilities if the data is later retrieved and displayed or processed without proper sanitization.
  3. Framework-Provided Sanitization: Utilize built-in sanitization functions provided by the application's framework or language to ensure consistent and reliable sanitization across the application.
• List of Threats Mitigated:
  • Cross-Site Scripting (XSS) via OCR Output (High Severity): OCR output derived from a maliciously crafted image could contain embedded malicious scripts or HTML. Displaying this unsanitized output in the application can lead to XSS attacks, potentially compromising user accounts, stealing sensitive information, or manipulating application functionality.
• Impact:
  • Cross-Site Scripting (XSS): High risk reduction. Effectively prevents XSS attacks that could originate from malicious content within the OCR output generated by tesseract.js.
• Currently Implemented: HTML escaping is used when displaying OCR output in the main results area of the application.
• Missing Implementation: Sanitization is not consistently applied in all areas where OCR output is used, particularly in JavaScript logic that processes the output for further actions (e.g., searching, data extraction, dynamic UI updates based on OCR results).

Mitigation Strategy: Set Processing Timeouts for tesseract.js

5. Set Processing Timeouts for tesseract.js

• Mitigation Strategy: Set Processing Timeouts for tesseract.js
• Description:
  1. Configure tesseract.js Timeout Options: Explore the tesseract.js API documentation and configuration options to identify if there are built-in mechanisms to set timeouts for OCR processing tasks. If available, configure a reasonable timeout value that is sufficient for processing typical images but will prevent excessively long processing times.
  2. Implement JavaScript-Based Timeouts (If Necessary): If tesseract.js doesn't offer direct timeout configuration, implement JavaScript-based timeout mechanisms around the tesseract.js.recognize() function call. Use Promise.race() or similar techniques to set a time limit for the OCR operation and abort it if it exceeds the limit.
  3. Error Handling for Timeouts: Implement proper error handling to gracefully manage timeout situations. When a timeout occurs, ensure the application handles the error without crashing and informs the user that the OCR process timed out, suggesting potential reasons (e.g., complex image) and options (e.g., retry with a simpler image).
• List of Threats Mitigated:
  • Denial of Service (DoS) via Long-Running tesseract.js Tasks (Medium Severity): Prevents tesseract.js from getting stuck processing extremely complex or maliciously crafted images that could lead to prolonged resource consumption (CPU, memory, browser responsiveness) on the client-side or server-side if OCR is performed there. This helps prevent DoS conditions caused by tying up resources with never-ending OCR tasks.
• Impact:
  • Denial of Service (DoS) via tesseract.js: Medium risk reduction. Reduces the impact of DoS attacks that rely on causing tesseract.js to consume resources indefinitely.
• Currently Implemented: No explicit processing timeouts are configured for tesseract.js.
• Missing Implementation: Implementation of timeouts for tesseract.js processing is missing.

Mitigation Strategy: Regularly Update tesseract.js and Dependencies

6. Regularly Update tesseract.js and Dependencies

• Mitigation Strategy: Regularly Update tesseract.js and Dependencies
• Description:
  1. Dependency Management: Utilize a package manager (like npm or yarn) to manage tesseract.js and its dependencies. This makes updating easier and tracks versions.
  2. Monitoring for Updates: Regularly monitor for new releases and security updates for tesseract.js and its dependencies. Subscribe to security mailing lists, check release notes, and use tools that can notify you of outdated dependencies.
  3. Testing Updates: Before deploying updates to a production environment, thoroughly test them in a staging or development environment to ensure compatibility with the application and prevent regressions. Verify that the updates do not introduce new issues or break existing functionality, including OCR accuracy and performance.
  4. Timely Updates: Apply updates promptly, especially security-related updates, to minimize the window of vulnerability exploitation.
• List of Threats Mitigated:
  • Known Vulnerabilities in tesseract.js or Dependencies (Severity Varies - Can be High): Outdated versions of tesseract.js or its dependencies may contain publicly known security vulnerabilities. Regularly updating to the latest versions (including patch updates) ensures that known vulnerabilities are addressed and reduces the risk of exploitation by attackers targeting these known weaknesses.
• Impact:
  • Known Vulnerabilities: High risk reduction over time. Proactively addresses known vulnerabilities in tesseract.js and its ecosystem, reducing the likelihood of exploitation.
• Currently Implemented: Dependency management is in place using npm.
• Missing Implementation: Regular, scheduled checks for updates and a defined process for testing and applying updates are missing.

Mitigation Strategy: Dependency Scanning for tesseract.js

7. Dependency Scanning for tesseract.js

• Mitigation Strategy: Dependency Scanning for tesseract.js
• Description:
  1. Choose a Dependency Scanning Tool: Select a suitable dependency scanning tool (e.g., Snyk, OWASP Dependency-Check, npm audit, or GitHub Dependabot) that can scan JavaScript dependencies, including tesseract.js.
  2. Integrate into Development Pipeline: Integrate the chosen dependency scanning tool into the development and CI/CD pipelines. This ensures that dependencies are automatically scanned for vulnerabilities during development and before deployment.
  3. Automated Scans: Configure the tool to automatically scan dependencies for known vulnerabilities on a regular basis (e.g., daily, weekly, or on each commit/pull request).
  4. Vulnerability Reporting and Remediation Workflow: Set up alerts and notifications for detected vulnerabilities. Establish a clear workflow for reviewing vulnerability reports, prioritizing remediation based on severity and exploitability, and updating tesseract.js or its dependencies to patched versions or implementing workarounds if patches are not immediately available.
• List of Threats Mitigated:
  • Known Vulnerabilities in tesseract.js or Dependencies (Severity Varies - Can be High): Proactively identifies known security vulnerabilities in tesseract.js and its dependencies before they can be exploited. This allows for timely remediation and reduces the risk of using vulnerable components in the application.
• Impact:
  • Known Vulnerabilities: High risk reduction. Significantly improves the ability to proactively identify and address known vulnerabilities specifically within tesseract.js and its dependency chain.
• Currently Implemented: No dependency scanning is currently implemented.
• Missing Implementation: Integration of a dependency scanning tool into the development and CI/CD pipelines is missing.