threat-modeling.md

Threat Model Analysis for asciinema/asciinema-player

Threat: DOM-based Cross-Site Scripting (XSS)

• Description: An attacker crafts a malicious asciinema recording containing JavaScript code embedded within the recording data (e.g., in terminal output or control sequences). When the player renders this recording, the malicious JavaScript is executed in the user's browser within the application's origin. This could be achieved by manipulating the JSON structure of the recording or encoding malicious scripts within terminal escape sequences.
  • Impact:
    • Account takeover: Attacker can steal session cookies or credentials.
    • Data theft: Attacker can access sensitive data within the application.
    • Malware distribution: Attacker can redirect users to malicious websites or inject malware.
    • Defacement: Attacker can alter the visual appearance of the web page.
  • Affected Component: asciinema-player core rendering logic, specifically the parts responsible for processing and displaying terminal output and control sequences.
  • Risk Severity: High
  • Mitigation Strategies:
    • Input Sanitization (Server-side): If recordings are sourced from users or untrusted origins, implement robust server-side validation and sanitization of the asciinema recording data before serving it to the client. This should include stripping potentially harmful control sequences and validating the JSON structure.
    • Content Security Policy (CSP): Implement a strict CSP that restricts the sources from which JavaScript can be executed and limits the capabilities of inline scripts. While CSP might not fully prevent all DOM-based XSS, it can significantly reduce the impact.
    • Regular Updates: Keep asciinema-player updated to the latest version to benefit from security patches that address potential XSS vulnerabilities.