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Mitigation Strategies Analysis for mingrammer/diagrams

Mitigation Strategy: Strict Input Validation and Sanitization for Diagram Content

1. Mitigation Strategy: Strict Input Validation and Sanitization for Diagram Content

  • Description:

    1. Identify All Diagram Input Sources: Pinpoint every source of data that feeds into the diagram's structure and content (node labels, edge connections, cluster groupings, attributes, etc.). This includes user inputs, API responses, database results, and configuration settings used specifically for diagram generation.
    2. Define Diagram-Specific Whitelists: For each input field that affects the diagram, create a strict whitelist. This whitelist defines the allowed data types, formats, and values. Examples:
      • Node Labels: Regular expressions for valid server names, application names, etc.
      • Node Types: Enumerated lists of allowed node types (e.g., "Database", "WebServer", "LoadBalancer").
      • Edge Connections: Rules defining which node types can connect to each other.
      • Cluster Groupings: Rules defining how nodes can be grouped into clusters.
    3. Implement Diagram-Specific Validation: Before passing any data to the diagrams library's API, rigorously validate it against the corresponding whitelist. Reject any input that doesn't conform. Use a validation library or framework to handle complex validation logic and prevent bypasses.
    4. Sanitize Diagram Data (Redaction/Obfuscation): If data must be included in the diagram but contains sensitive parts, sanitize it before it's used by diagrams.
      • Redaction: Replace sensitive parts with placeholders (e.g., "API Key: [REDACTED]").
      • Obfuscation: Transform sensitive data (e.g., hash an identifier).
      • Tokenization: Replace sensitive data with a non-sensitive token within the diagram. The mapping between token and data is stored securely elsewhere.
    5. Diagram-Specific Error Handling: Implement robust error handling for validation failures within the diagram generation code. Do not include sensitive information in error messages that might be exposed through the diagram. Log validation errors securely.
    6. Regular Review of Diagram Logic: Periodically review the whitelists, validation logic, and sanitization routines specifically related to diagram generation to ensure they remain effective and up-to-date.

  • Threats Mitigated:

    • Data Leakage through Diagram Content (Severity: High): Prevents sensitive information from being embedded directly within the generated diagrams.
    • Denial of Service (DoS) via Complex Diagrams (Severity: Medium): Limits diagram complexity by controlling the input used to define the diagram's structure.
    • Cross-Site Scripting (XSS) via Diagram Labels/Tooltips (Severity: Low/Medium): Prevents malicious code injection through user-supplied input that becomes part of the diagram's visual representation (primarily relevant for SVG output).

  • Impact:

    • Data Leakage: Significantly reduces the risk, with effectiveness depending on whitelist comprehensiveness and sanitization rigor.
    • DoS: Reduces the likelihood of DoS by limiting diagram complexity.
    • XSS: Eliminates the primary XSS vector related to diagram content.

  • Currently Implemented:

    • Partial input validation exists in diagram_input_handler.py, but it's basic and doesn't use whitelists.
    • No sanitization is implemented.

  • Missing Implementation:

    • Whitelist-based validation for all diagram-related inputs.
    • Sanitization (redaction, obfuscation, tokenization) for sensitive data.
    • Comprehensive, diagram-specific error handling.
    • Regular review process for diagram generation logic.

Mitigation Strategy: Avoid Sensitive Data in Diagrams (Design-Level)

2. Mitigation Strategy: Avoid Sensitive Data in Diagrams (Design-Level)

  • Description:

    1. Diagram Design Review: Conduct a thorough review of all diagram templates and generation logic to identify any places where sensitive data is currently included or could potentially be included.
    2. Mandatory Abstraction: Enforce a strict policy: never include raw sensitive data (credentials, PII, internal IPs, etc.) directly in diagrams. Replace them with abstract representations.
      • Instead of "DB Server (192.168.1.10:5432, user=admin, password=secret)", use "Database Server".
      • Instead of "API Key: abcdefg1234567", use "API Endpoint (Authorized)".
      • Instead of user email addresses, use "User 1", "User 2", or role-based labels.
    3. Tokenization (If Identifiers Are Needed): If specific identifiers are absolutely required for the diagram's purpose, use tokens within the diagram. The diagram displays the token; a separate, secure system handles the mapping between the token and the actual sensitive value. This keeps the sensitive data out of the diagram itself.
    4. Document the "No Sensitive Data" Policy: Clearly document this policy, providing examples of acceptable abstract representations and the rationale behind it. This documentation should be readily available to all developers working with the diagram generation code.
    5. Enforce via Code Review: Make this policy a mandatory check during code reviews. Any code that attempts to include sensitive data directly in diagrams should be rejected and corrected.

  • Threats Mitigated:

    • Data Leakage through Diagram Content (Severity: High): Eliminates the root cause by preventing sensitive data from ever being part of the diagram.

  • Impact:

    • Data Leakage: Provides the strongest protection, as sensitive data is never present in the diagrams.

  • Currently Implemented:

    • Informal understanding among developers, but no formal policy or enforcement.

  • Missing Implementation:

    • Formal diagram design review process.
    • Written documentation of the policy and examples.
    • Mandatory code review checks.
    • Tokenization is not used.

Mitigation Strategy: Input Validation and Limitation for DoS (Diagram-Specific)

3. Mitigation Strategy: Input Validation and Limitation for DoS (Diagram-Specific)

  • Description:

    1. Identify Diagram Complexity Factors: Determine the specific elements within the diagrams library's usage that contribute to generation time and resource consumption. This includes:
      • Number of nodes.
      • Number of edges.
      • Depth of nested clusters.
      • Number and size of text labels.
      • Use of custom images or icons.
      • Specific diagrams features that might be computationally expensive.
    2. Define Diagram-Specific Limits: Establish reasonable limits for each of these complexity factors, based on expected use cases and available resources. These limits should be tailored to the diagrams library's capabilities and performance characteristics.
    3. Implement Pre-Generation Validation: Implement validation checks before calling the diagrams library's functions. These checks enforce the defined limits. Reject any input that would result in a diagram exceeding these limits.
    4. Timeouts (Specific to Diagram Generation): Implement a timeout mechanism specifically for the diagram generation process. If the diagrams library call takes longer than a predefined threshold (e.g., 10-30 seconds), terminate the process. This prevents a single complex diagram from consuming excessive resources.
    5. Rate Limiting (If User-Triggered): If diagram generation is initiated by user actions, implement rate limiting specifically for the diagram generation endpoint. This prevents a user from submitting numerous requests that, while individually valid, could collectively cause a DoS.

  • Threats Mitigated:

    • Denial of Service (DoS) via Complex Diagrams (Severity: Medium): Prevents attackers from causing resource exhaustion by submitting inputs that would generate overly complex diagrams.

  • Impact:

    • DoS: Significantly reduces the likelihood of DoS attacks specifically targeting the diagram generation functionality.

  • Currently Implemented:

    • No specific diagram-related input limitations.
    • A general timeout exists, but it's too high (5 minutes).

  • Missing Implementation:

    • Definition and enforcement of limits on diagram complexity factors.
    • A dedicated, shorter timeout for the diagram generation process.
    • Rate limiting for user-triggered diagram generation.

Mitigation Strategy: Output Encoding for XSS (Diagram-Specific, SVG Focus)

4. Mitigation Strategy: Output Encoding for XSS (Diagram-Specific, SVG Focus)

  • Description:

    1. Identify Diagram Output Format: Determine the output format used by diagrams (PNG, SVG, etc.). This strategy is primarily relevant for SVG output.
    2. Mandatory Output Encoding (SVG): If the output is SVG and it's displayed in a web context:
      • Templating Engine: Use a templating engine (Jinja2, Django templates, etc.) that automatically performs HTML encoding of all text content within the SVG (node labels, tooltips, edge labels, any other text). This is the preferred approach.
      • Manual Escaping (If Necessary): If you're manually constructing the SVG output (not recommended), use appropriate escaping functions (e.g., html.escape() in Python) to encode all text content before embedding it in the SVG. Ensure attributes are properly quoted.
    3. Input Sanitization (Defense-in-Depth): Even with output encoding, always sanitize any user-provided input that might end up in the diagram. This removes potentially malicious HTML or JavaScript before it even reaches the diagram generation stage. This is a crucial defense-in-depth measure.

  • Threats Mitigated:

    • Cross-Site Scripting (XSS) via Diagram Labels/Tooltips (Severity: Low/Medium): Prevents the injection of malicious scripts through diagram content, specifically when using SVG output.

  • Impact:

    • XSS: Significantly reduces the risk of XSS. Output encoding is the primary defense. Input sanitization adds another layer.

  • Currently Implemented:

    • Diagrams are currently PNG, reducing XSS risk.
    • No output encoding is performed.

  • Missing Implementation:

    • If SVG output is ever used, output encoding must be implemented.
    • Input sanitization should be reviewed and reinforced.