threat-modeling.md

Threat Model Analysis for square/okio

Threat: Data Injection via Stream Manipulation

• Description: An attacker injects malicious data into a data stream (e.g., network socket, file stream) that is being read by the application using Okio's Source API. The attacker aims to insert commands, scripts, or other malicious payloads into the stream. If the application processes this stream content without proper sanitization, it could lead to injection vulnerabilities.
• Impact: Command Injection, Cross-Site Scripting (XSS), SQL Injection (if stream data is used in database queries), or other injection-based attacks, depending on how the application processes the stream content.
• Okio Component Affected: Source, BufferedSource, Sink, BufferedSink (if the application also writes back based on the stream).
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Sanitize and validate data read from untrusted streams after reading with Okio but before using it in any sensitive operations.
  • Use output encoding when displaying data derived from streams in web contexts to prevent XSS.
  • Avoid directly executing commands or interpreting stream data as code without strict validation and sandboxing.
  • Apply the principle of least privilege to the application's access to system resources.

Threat: Path Traversal via File System Operations

• Description: An attacker provides a manipulated file path as input to the application, which then uses Okio's FileSystem APIs (e.g., FileSystem.source, FileSystem.sink, Path operations) to access files. By using path traversal sequences like ../ or absolute paths, the attacker can attempt to access files outside of the intended directory, potentially gaining access to sensitive data or system files.
• Impact: Unauthorized access to sensitive files, data breaches, potential system compromise if sensitive system files are accessed.
• Okio Component Affected: FileSystem, Path, FileSystem.source, FileSystem.sink, FileSystem.delete, FileSystem.createDirectory, etc.
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Thoroughly validate and sanitize all user-provided file paths before using them with Okio's file system operations.
  • Use allow-lists to restrict allowed file paths or filenames to a specific directory or set of directories.
  • Normalize paths to remove path traversal sequences.
  • Consider using chroot jails or similar sandboxing techniques to restrict the application's file system access.
  • Avoid directly using user-provided paths for file operations whenever possible.

Threat: Symbolic Link Exploitation

• Description: An attacker creates or manipulates symbolic links on the file system. If the application uses Okio to interact with files through paths that might resolve through these symbolic links, the attacker can potentially redirect file operations to unintended targets, including sensitive files or directories.
• Impact: Unauthorized access to sensitive files, data modification, potential system compromise if operations are redirected to critical system files.
• Okio Component Affected: FileSystem, Path, FileSystem.source, FileSystem.sink, FileSystem.exists, FileSystem.metadata, etc. (any function that resolves paths).
• Risk Severity: High
• Mitigation Strategies:
  • Be aware of symbolic links when dealing with file paths, especially those from untrusted sources.
  • If possible, avoid following symbolic links.
  • If symbolic links must be followed, implement checks to verify that the resolved path is within expected boundaries and does not lead to unintended resources.
  • Consider using Path.toRealPath() with NOFOLLOW_LINKS option (if available in the specific Okio environment) to resolve paths without following symbolic links.

Threat: Dependency Vulnerability (Okio Library)

• Description: A security vulnerability is discovered in the Okio library itself. Attackers can exploit this vulnerability if the application uses a vulnerable version of Okio. Exploitation methods depend on the specific vulnerability.
• Impact: Varies depending on the vulnerability. Could range from Denial of Service to Remote Code Execution or Data Breaches.
• Okio Component Affected: Potentially any component of Okio, depending on the specific vulnerability.
• Risk Severity: Varies (can be Critical or High depending on the vulnerability)
• Mitigation Strategies:
  • Keep the Okio library updated to the latest stable version.
  • Subscribe to security advisories and vulnerability databases related to Okio (e.g., GitHub Security Advisories, CVE databases).
  • Regularly review and update dependencies to patch known vulnerabilities.
  • Implement a vulnerability scanning process for dependencies.