mitigations.md

Mitigation Strategies Analysis for symfony/finder

Mitigation Strategy: Use Absolute Paths and Restrict Search Scope with in()

• Description:

  1. When using the Finder->in() method, always provide absolute paths to the starting directories. This ensures Finder operates within a predictable and controlled file system area.
  2. Limit the number of directories passed to Finder->in() to the minimum necessary for the application's functionality. Avoid broad or unnecessary directory inclusions.
  3. Predefine allowed base directories in application configuration instead of dynamically constructing them based on user input.
  4. Where possible, restrict the search to a single, well-defined directory using Finder->in() rather than allowing searches across multiple disparate locations.

• Threats Mitigated:

  • Path Traversal (Medium Severity) - By using absolute paths and limiting the search scope, you reduce the risk of Finder being directed to traverse unintended areas of the file system, even if input validation elsewhere is bypassed.
  • Information Disclosure (Low Severity) - Restricting the search scope minimizes the chance of Finder inadvertently including sensitive files in its results if search criteria are too broad.

• Impact:

  • Path Traversal: Partially Reduced - Limits the exploitable area if other path validation fails, confining potential traversal within the explicitly allowed base directories.
  • Information Disclosure: Minimally Reduced - Decreases the likelihood of accidental exposure by narrowing down the search area.

• Currently Implemented:

  • Partially implemented. The file management module uses absolute paths for the primary directory it browses, but the in() method might still be used with dynamically constructed subpaths within that base.

• Missing Implementation:

  • The backup module's configuration allows specifying a relative path for the backup source directory. This should be changed to enforce absolute paths within the Finder->in() configuration to prevent accidental broadening of the backup scope.

Mitigation Strategy: Limit Search Depth and Scope using depth(), name(), and path()

• Description:

  1. Utilize the Finder->depth() method to restrict the maximum depth of directory traversal. Set a reasonable depth limit based on the expected directory structure and application needs.
  2. Employ the Finder->name() and Finder->path() methods with specific file name patterns or path patterns to precisely define the search scope. Avoid overly permissive patterns like * or very general path patterns.
  3. Combine Finder->depth(), Finder->name(), and Finder->path() to create highly specific search criteria that minimize the number of files and directories Finder processes, improving performance and reducing potential attack surface.

• Threats Mitigated:

  • Denial of Service (DoS) (Medium Severity) - Prevents Finder from traversing excessively deep or large directory structures, which could lead to resource exhaustion and DoS. Limiting scope reduces the processing load.
  • Information Disclosure (Low Severity) - Reduces the risk of unintentionally including sensitive files in search results by narrowing the search to only relevant files and directories.

• Impact:

  • Denial of Service (DoS): Partially Reduced - Limits resource consumption by preventing overly broad searches, making it harder for attackers to trigger resource exhaustion through Finder.
  • Information Disclosure: Minimally Reduced - Decreases the chance of accidental exposure by limiting the search area to what is strictly necessary.

• Currently Implemented:

  • Implemented in the application's search functionality. Finder->depth() is limited to 3 levels, and Finder->name() is used to filter file types.

• Missing Implementation:

  • The log analysis tool, which uses Finder to scan log files, does not currently use Finder->depth() to limit traversal. Adding a depth limit would improve performance and resilience against DoS if log directories become very deep.

Mitigation Strategy: Implement Timeouts for Finder Operations

• Description:

  1. Set a timeout for Finder operations to prevent them from running indefinitely, especially when dealing with potentially large file systems or complex search criteria.
  2. Use PHP's set_time_limit() function before initiating Finder operations. This will limit the execution time of the script, including the Finder processing.
  3. Implement error handling to catch timeout exceptions or errors. Gracefully handle timeouts by stopping the Finder operation and informing the user or logging the event.

• Threats Mitigated:

  • Denial of Service (DoS) (Medium Severity) - Prevents Finder operations from consuming server resources for an unlimited time, mitigating DoS attacks that exploit long-running file system operations.

• Impact:

  • Denial of Service (DoS): Partially Reduced - Limits the impact of prolonged Finder operations, preventing complete resource exhaustion in DoS scenarios. However, it might not prevent rapid, repeated requests that still overload the server within the timeout period.

• Currently Implemented:

  • Not implemented. Finder operations are currently executed without explicit timeouts.

• Missing Implementation:

  • Timeouts should be implemented for all user-facing Finder operations, such as file browsing and search, and also for background tasks that utilize Finder, like log processing and backups, to ensure system stability under load or attack.

Mitigation Strategy: Avoid Complex or User-Controlled Regular Expressions in name() and path()

• Description:

  1. Minimize the use of complex regular expressions within the Finder->name() and Finder->path() methods. Simpler string matching or glob patterns are generally safer and less resource-intensive.
  2. Never directly use user-provided input to construct regular expressions for Finder. If regex-based filtering is necessary based on user input, rigorously sanitize and validate the input to prevent injection of malicious regex patterns.
  3. If complex regular expressions are unavoidable, thoroughly test them for performance and potential backtracking issues that could lead to Regular Expression Denial of Service (ReDoS).

• Threats Mitigated:

  • Regular Expression Denial of Service (ReDoS) (Medium Severity) - Prevents attackers from injecting or providing malicious regular expressions that cause excessive backtracking in Finder's regex matching, leading to DoS.

• Impact:

  • Regular Expression Denial of Service (ReDoS): Partially Reduced - Avoiding complex or user-controlled regexes significantly reduces the attack surface for ReDoS vulnerabilities within Finder operations.

• Currently Implemented:

  • Partially implemented. Most Finder operations use simpler glob patterns. However, the log analysis tool utilizes regular expressions for more advanced log filtering.

• Missing Implementation:

  • The regular expressions used in the log analysis tool should be reviewed for complexity and potential ReDoS vulnerabilities. If user-defined regex filters are planned for the log analysis or other features, robust input sanitization and validation, or alternative safer filtering methods, must be implemented to prevent ReDoS attacks.