Skip to content

Latest commit

 

History

History
53 lines (46 loc) · 7.05 KB

attack-surface.md

File metadata and controls

53 lines (46 loc) · 7.05 KB

Attack Surface Analysis for usememos/memos

Attack Surface: Memo Content Manipulation (Direct Injection)

  • Description: Attacks exploiting how memos processes and renders user-supplied memo content (Markdown, HTML, or other supported formats) to inject malicious code or data. This is distinct from general XSS, as it focuses on the specific parsing and rendering logic of memos.
  • How memos Contributes: memos's primary function is accepting, storing, and displaying user-generated content. The Markdown rendering engine, any custom rendering logic, and handling of embedded resources (images, links, iframes if allowed) are all direct contributors to this attack surface.
  • Example: An attacker crafts a memo with malicious Markdown that exploits a vulnerability in the specific Markdown parser used by memos to achieve remote code execution (RCE) on the server or execute arbitrary JavaScript in the browsers of other users. Another example: if memos allows certain HTML tags, an attacker might use these to bypass sanitization and inject malicious scripts.
  • Impact: Server compromise (RCE), user account compromise, data theft, defacement, malware distribution, denial of service.
  • Risk Severity: Critical (if RCE is possible) or High (for client-side attacks like XSS).
  • Mitigation Strategies:
    • Developers:
      • Use a securely configured, well-vetted, and up-to-date Markdown parser known for its security. Avoid custom or less-common parsers unless they have undergone rigorous security review.
      • Implement strict input validation before Markdown processing, rejecting any input that doesn't conform to a tightly defined whitelist of allowed characters and structures.
      • Employ a strong Content Security Policy (CSP) to limit the types of content that can be loaded and executed within the memos context. This is a critical defense-in-depth measure, even with a secure parser.
      • Sanitize the output of the Markdown parser (the generated HTML) to ensure that only safe HTML is rendered. This acts as a second layer of defense.
      • If supporting file uploads (images, etc.), implement rigorous file type validation (checking the actual file content, not just the extension), size limits, and consider virus scanning. Store uploaded files securely, ideally outside the web root.
      • Regularly audit the entire content processing pipeline (input validation, Markdown parsing, output sanitization, file handling) for vulnerabilities.
      • If plugins or custom rendering are allowed, implement a robust sandboxing mechanism and a strict permission system. This is extremely important if extending functionality.

Attack Surface: Unauthorized Memo Access (Bypassing Access Controls)

  • Description: Attacks that bypass memos's built-in access control mechanisms (public/private/protected visibility, user roles) to view, modify, or delete memos without proper authorization.
  • How memos Contributes: memos provides features for controlling memo visibility and potentially user permissions. The logic that enforces these features is the direct attack surface.
  • Example: An attacker exploits an IDOR (Insecure Direct Object Reference) vulnerability by manipulating the memo ID in a URL or API request to access a private memo that belongs to another user. Or, an attacker exploits a flaw in the session management to impersonate another user and gain access to their private memos.
  • Impact: Data breaches (exposure of private information), privacy violations, unauthorized modification or deletion of memos.
  • Risk Severity: High or Critical (depending on the sensitivity of the data exposed and the level of access gained).
  • Mitigation Strategies:
    • Developers:
      • Implement robust authentication and authorization checks on every server-side request that accesses or modifies memo data. Never rely solely on client-side checks.
      • Use a consistent and well-tested authorization framework or library.
      • Avoid predictable resource identifiers (e.g., sequential IDs). Use UUIDs or other unpredictable identifiers for memos and other resources.
      • Thoroughly test all access control logic, including edge cases, concurrent requests, and different user roles/permissions.
      • Implement secure session management, using strong, randomly generated session IDs, HTTPS, and appropriate session timeouts and invalidation.
      • Regularly audit the access control implementation and conduct penetration testing.

Attack Surface: API Abuse (Targeting memos-Specific Endpoints)

  • Description: Attacks specifically targeting the memos API to perform unauthorized actions, extract data, or cause denial of service. This focuses on vulnerabilities within the API's design and implementation, not general API security principles.
  • How memos Contributes: memos exposes an API for interacting with the application. The design and implementation of these specific API endpoints are the direct attack surface.
  • Example: An attacker discovers an undocumented or poorly secured API endpoint in memos that allows them to bypass authentication and create, modify, or delete memos. Or, an attacker exploits a vulnerability in a specific API endpoint's parameter handling to inject malicious code. Another example is an attacker using the API to rapidly create memos, exceeding rate limits and causing a denial of service.
  • Impact: Denial of service, data breaches, unauthorized access to memos, system compromise (if RCE is possible).
  • Risk Severity: High or Critical (depending on the specific vulnerability and its impact).
  • Mitigation Strategies:
    • Developers:
      • Require strong authentication for all memos API endpoints that access or modify data.
      • Implement strict input validation and sanitization for all API parameters, specific to the expected data type and format for each endpoint.
      • Implement robust rate limiting and throttling on all API requests, with different limits potentially applied to different endpoints and user roles.
      • Use a well-defined API specification (e.g., OpenAPI/Swagger) and keep it up-to-date. This helps with both security and maintainability.
      • Securely handle API keys and tokens. Avoid hardcoding them. Use appropriate expiration and revocation mechanisms.
      • Log all API requests, including successful and failed attempts, for auditing and security monitoring.
      • Regularly perform security audits and penetration testing specifically targeting the memos API.
      • Avoid exposing unnecessary information in API responses or error messages. Be careful about revealing internal implementation details.