threat-modeling.md

Threat Model Analysis for baseflow/photoview

Threat: Large Image Denial of Service (DoS)

• Description: An attacker provides or links to an extremely large image file (in terms of resolution or file size). When a user attempts to view this image using photoview, the library instructs the browser to load and render it. This can overwhelm the user's browser or device resources (CPU, memory) leading to unresponsiveness, slowdown, or crashing. The attacker's goal is to disrupt the application's availability for legitimate users by targeting client-side resources through image display functionality provided by photoview.
• Impact: Denial of Service for users attempting to view specific images, severely impacting application availability and user experience. In extreme cases, it can lead to browser or device crashes.
• PhotoView Component Affected: photoview library's core functionality of loading and rendering images, specifically when handling extremely large images. While the browser's rendering engine is ultimately stressed, photoview initiates and manages the image display process that leads to resource exhaustion.
• Risk Severity: High
• Mitigation Strategies:
  • Implement strict server-side image size and dimension limits to prevent serving excessively large images.
  • Perform server-side image optimization (compression, resizing) to reduce image size before delivery.
  • Consider implementing client-side checks within the application using photoview to prevent loading images exceeding certain size thresholds if feasible.
  • Utilize lazy loading or image tiling techniques, especially for applications expected to handle very large images, to reduce initial resource load when using photoview.
  • Implement rate limiting on image requests if necessary to mitigate automated attempts to trigger DoS by repeatedly requesting large images.

Threat: Malicious Image Rendering Crash (DoS)

• Description: An attacker crafts or modifies image files to exploit known or zero-day vulnerabilities in browser image decoding or rendering engines. When photoview is used to display such a malicious image, it triggers the browser's rendering engine to process the file, potentially leading to a crash due to the exploited vulnerability. The attacker aims to cause a Denial of Service by leveraging vulnerabilities in image processing triggered through photoview's image display functionality.
• Impact: Application crash or unexpected behavior when viewing a malicious image, resulting in Denial of Service. In more severe scenarios, successful exploitation of rendering engine vulnerabilities could potentially lead to further security breaches beyond DoS, although less likely directly through photoview itself.
• PhotoView Component Affected: photoview library's image display functionality acts as a trigger, causing the browser's image rendering engine to process potentially malicious image data. While the vulnerability resides in the browser's engine, photoview's role in displaying the image makes it a component involved in the threat chain.
• Risk Severity: High
• Mitigation Strategies:
  • Implement robust server-side image validation and sanitization to detect and reject potentially malicious image files before they are served and displayed by photoview. This includes using image processing libraries to analyze and verify image integrity.
  • Ensure that both the server and client-side environments (browsers) are kept up-to-date with the latest security patches for image decoding and rendering libraries to minimize known vulnerabilities.
  • Consider using a sandboxed environment for image processing if feasible and if the application architecture allows for it, although this is generally a browser-level security feature.
  • Regularly monitor security advisories related to browser vulnerabilities and image processing libraries to proactively address potential threats.