Skip to content

Latest commit

 

History

History
77 lines (68 loc) · 7.14 KB

attack-surface.md

File metadata and controls

77 lines (68 loc) · 7.14 KB

Attack Surface Analysis for lemmynet/lemmy

Attack Surface: Malicious Federated Content Injection

  • Description: A malicious or compromised federated Lemmy instance injects harmful content into your instance via the ActivityPub protocol.
  • Lemmy Contribution: Lemmy's core functionality relies on federation using ActivityPub to connect with other instances and share content. This inherently trusts content received from federated sources.
  • Example: A malicious instance sends posts and comments to your instance containing embedded JavaScript code. When users on your instance view this content, the JavaScript executes, stealing session cookies and compromising their accounts.
  • Impact:
    • Cross-Site Scripting (XSS) attacks leading to account compromise, data theft, and website defacement.
    • Spread of misinformation and spam, degrading user experience and trust.
  • Risk Severity: High
  • Mitigation Strategies:
    • Developers:
      • Robust Input Sanitization and Output Encoding: Strictly sanitize and encode all content received from federated instances before rendering it in the frontend. Focus on preventing XSS vulnerabilities.
      • Content Security Policy (CSP): Implement a strong CSP to limit the sources from which the browser can load resources, mitigating the impact of XSS.
      • Regular Security Audits: Conduct regular security audits of the frontend and backend code, specifically focusing on federation handling and content rendering.
    • Users/Administrators:
      • Instance Monitoring: Monitor your instance for suspicious content originating from federated instances.
      • Moderation Policies: Establish clear moderation policies to quickly identify and remove malicious federated content.

Attack Surface: ActivityPub Resource Exhaustion (DoS)

  • Description: A malicious federated instance or attacker floods your Lemmy instance with a massive volume of ActivityPub requests, overwhelming server resources and causing a Denial of Service (DoS).
  • Lemmy Contribution: Lemmy's federation model relies on receiving and processing ActivityPub requests from other instances. If not properly protected, this can be abused for DoS attacks.
  • Example: A malicious actor sets up a botnet of federated instances to send a flood of follow requests, post deliveries, or other ActivityPub actions to your instance, exceeding its processing capacity and making it unavailable to legitimate users.
  • Impact:
    • Denial of Service (DoS), making the Lemmy instance unavailable.
    • Performance degradation for legitimate users.
    • Potential server instability and crashes.
  • Risk Severity: High
  • Mitigation Strategies:
    • Developers:
      • Rate Limiting: Implement robust rate limiting on ActivityPub endpoints to restrict the number of requests from individual instances or IP addresses within a given timeframe.
      • Request Queuing and Throttling: Implement request queuing and throttling mechanisms to manage incoming ActivityPub requests and prevent overload.
      • Resource Monitoring and Alerting: Implement monitoring of server resources (CPU, memory, network) and set up alerts to detect unusual spikes in ActivityPub traffic.
    • Users/Administrators:
      • Firewall and Network Security: Configure firewalls and network security measures to filter malicious traffic and potentially block known malicious IP ranges.
      • Instance Monitoring and Alerting: Monitor server performance and set up alerts for resource exhaustion.

Attack Surface: API Authentication and Authorization Flaws

  • Description: Weaknesses in Lemmy's API authentication and authorization mechanisms allow attackers to bypass security controls and gain unauthorized access or perform actions beyond their privileges.
  • Lemmy Contribution: Lemmy exposes a backend API for frontend interaction and potentially for external integrations. Vulnerabilities in API security directly impact the application's overall security.
  • Example: An attacker discovers an API endpoint that lacks proper authentication or has a flawed authorization check. They exploit this to directly access and modify user data, create administrative accounts, or perform other privileged actions without legitimate credentials.
  • Impact:
    • Unauthorized data access and modification.
    • Account compromise and takeover.
    • Privilege escalation, allowing attackers to gain administrative control.
    • Data breaches and privacy violations.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developers:
      • Strong Authentication Mechanisms: Implement robust authentication mechanisms (e.g., JWT, OAuth 2.0) for API access.
      • Proper Authorization Checks: Enforce strict authorization checks at every API endpoint to ensure users can only access and modify resources they are permitted to.
      • Principle of Least Privilege: Design API access controls based on the principle of least privilege, granting users only the necessary permissions.
    • Users/Administrators:
      • Keep Lemmy Updated: Apply security updates and patches promptly to address known API vulnerabilities.

Attack Surface: Cross-Site Scripting (XSS) in Frontend

  • Description: Vulnerabilities in Lemmy's frontend code allow attackers to inject malicious JavaScript code that executes in users' browsers when they interact with the application.
  • Lemmy Contribution: Lemmy's frontend handles user-generated content and data from federated instances. Improper handling of this content can lead to XSS vulnerabilities.
  • Example: An attacker injects malicious JavaScript code into a post or comment. When another user views this post or comment, the JavaScript executes in their browser, stealing their session cookie and allowing the attacker to hijack their account.
  • Impact:
    • Account compromise and takeover.
    • Data theft and manipulation.
    • Website defacement and malicious redirects.
    • Spread of malware.
  • Risk Severity: High
  • Mitigation Strategies:
    • Developers:
      • Robust Output Encoding: Strictly encode all user-generated content and data from federated instances before rendering it in the frontend to prevent XSS. Use context-aware encoding.
      • Content Security Policy (CSP): Implement a strong CSP to mitigate the impact of XSS by restricting the sources from which the browser can load resources.
      • Regular Security Audits and Code Reviews: Conduct regular security audits and code reviews of the frontend code, specifically focusing on XSS prevention.
    • Users/Administrators:
      • Keep Lemmy Updated: Apply security updates and patches promptly to address known frontend vulnerabilities.