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Attack Surface Analysis for iawia002/lux

Attack Surface: Server-Side Request Forgery (SSRF)

  • Description: An attacker tricks the server into making requests to unintended locations, potentially accessing internal resources or external systems.
  • How Lux Contributes: lux's core function is to fetch data from URLs provided by the user. It's designed to interact with a wide range of websites, making it a prime target for SSRF. lux's handling of redirects and embedded URLs within fetched content is a key contributor.
  • Example:
    • Attacker provides a URL like https://www.example.com/video.mp4?url=http://169.254.169.254/latest/meta-data/iam/security-credentials/ (AWS metadata endpoint). If lux follows this redirect or embedded URL without proper validation, it could expose AWS credentials.
    • Attacker provides a URL like https://legit-video-site.com/playlist.m3u8, but the playlist.m3u8 file contains a segment URL pointing to file:///etc/passwd.
  • Impact: Access to internal services, sensitive data (credentials, configuration files), potential for remote code execution (RCE) if internal services are vulnerable.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Strict Allow-listing: Maintain a list of explicitly allowed domains and URL prefixes. Reject any URL that doesn't match the allow-list before passing it to lux. Do not rely on lux's internal validation.
    • Network Segmentation: Run the application using lux in a network environment that restricts access to internal resources. Use firewalls and network policies to limit outbound connections.
    • Dedicated SSRF Prevention Library: Use a library specifically designed to prevent SSRF.
    • Disable URL Redirection Following (If Possible): If redirects are not strictly required, configure lux (or the underlying HTTP client) to not follow them.
    • Input Validation: Validate every part of the URL (scheme, hostname, port, path, query parameters) using a robust URL parsing library. Reject unusual characters or patterns.

Attack Surface: Regular Expression Denial of Service (ReDoS)

  • Description: An attacker provides input that triggers a computationally expensive regular expression, causing the application to become unresponsive.
  • How Lux Contributes: lux uses regular expressions extensively within its site extractors to parse HTML, JSON, and other data formats. The vulnerability lies within lux's code.
  • Example: An attacker crafts a specially designed URL or modifies a legitimate website's content (if possible) to include a string that triggers catastrophic backtracking in one of lux's regular expressions. A regex like (a+)+$ with input aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa! can cause this.
  • Impact: Denial of service; the application becomes unavailable.
  • Risk Severity: High
  • Mitigation Strategies:
    • Review Regular Expressions: Carefully examine the regular expressions used in the lux extractors (especially for frequently used sites). Look for known ReDoS patterns.
    • Use a ReDoS Detection Tool: Employ static analysis tools to detect potentially vulnerable regular expressions.
    • Implement Timeouts: Set strict timeouts for regular expression matching within your application's interaction with lux. Terminate long-running matches.
    • Input Length Limits: Impose reasonable limits on input string lengths processed by lux's regular expressions.

Attack Surface: XML External Entity (XXE) Injection

  • Description: An attacker injects malicious XML entities, potentially leading to file disclosure or SSRF.
  • How Lux Contributes: If a site extractor within lux processes XML data and uses a vulnerable XML parser, XXE is possible. The vulnerability is within lux's handling of potentially untrusted XML from external sites.
  • Example: If a site provides metadata in XML, and lux's extractor for that site doesn't disable external entity resolution, an attacker could provide a URL to a page containing malicious XML.
  • Impact: Disclosure of local files, potential for SSRF.
  • Risk Severity: High
  • Mitigation Strategies:
    • Verify XML Parser Configuration: Confirm that any XML parser used within lux's relevant extractors has external entity resolution disabled. This is crucial; the application using lux might not have direct control over this.
    • Contribute to lux (if necessary): If you identify a vulnerable extractor, consider contributing a fix to the lux project to disable external entities.

Attack Surface: Infinite Playlist Loops/Resource Exhaustion (M3U8)

  • Description: Maliciously crafted M3U8 playlists can cause lux to enter infinite loops or consume excessive resources.
    • How Lux Contributes: lux has specific logic for handling M3U8 playlists, and this logic is the direct source of the vulnerability.
    • Example: An attacker provides a URL to an M3U8 playlist where #EXT-X-MEDIA-SEQUENCE is manipulated, or segments reference each other cyclically, causing lux to repeatedly download the same segments.
    • Impact: Denial of Service.
    • Risk Severity: High
    • Mitigation Strategies:
      • Limit Playlist Depth and Segment Count: Within your application's interaction with lux, set reasonable limits on playlist depth and segment count.
      • Timeouts: Implement timeouts for downloading segments and processing the playlist within your application's use of lux.
      • Resource Monitoring: Monitor resource usage to detect and prevent excessive consumption caused by lux.