Skip to content

Latest commit

 

History

History
49 lines (40 loc) · 6.38 KB

threat-modeling.md

File metadata and controls

49 lines (40 loc) · 6.38 KB

Threat Model Analysis for phpoffice/phppresentation

Threat: Malformed Presentation File Upload - Remote Code Execution (RCE)

  • Description: An attacker uploads a crafted presentation file (PPTX, ODP, etc.) designed to exploit vulnerabilities within PHPOffice/PHPPresentation's file parsing logic. Successful exploitation allows the attacker to execute arbitrary code on the server when the application processes this malicious file. This could be due to buffer overflows, format string bugs, or vulnerabilities in how the library handles specific file structures or embedded objects.
  • Impact: Complete compromise of the server. Attackers can steal data, manipulate system configurations, install malware, or cause a denial of service.
  • Affected Component: File Parsers (e.g., PPTX Reader, ODP Reader), potentially underlying XML or ZIP handling components, image processing modules.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Strict Input Validation: Implement robust server-side file type validation to ensure only expected presentation file formats are accepted.
    • File Size Limits: Enforce reasonable limits on the size of uploaded presentation files to reduce the attack surface and mitigate resource exhaustion.
    • Sandboxing/Isolation: Process uploaded presentation files in a sandboxed environment or containerized environment to limit the potential damage if exploitation occurs.
    • Regular Updates: Maintain PHPOffice/PHPPresentation and all its dependencies updated to the latest versions to patch known security vulnerabilities promptly.
    • Security Audits & Code Review: Conduct regular security audits and code reviews, specifically focusing on the integration points with PHPOffice/PHPPresentation and the library's configuration.

Threat: Malformed Presentation File Upload - Denial of Service (DoS)

  • Description: An attacker uploads a specially crafted presentation file that, when processed by PHPOffice/PHPPresentation, consumes excessive server resources (CPU, memory, disk I/O). This can be achieved through complex file structures, deeply nested elements, or features that trigger inefficient processing algorithms within the library.
  • Impact: Application slowdown, service unavailability for legitimate users, and potential server crash due to resource exhaustion.
  • Affected Component: File Parsers (e.g., PPTX Reader, ODP Reader), layout engine, image processing components, potentially core processing logic of the library.
  • Risk Severity: High
  • Mitigation Strategies:
    • File Size Limits: Implement and enforce file size limits for uploaded presentations.
    • Resource Limits: Configure resource limits (CPU time, memory usage) for the PHP processes handling presentation file processing.
    • Asynchronous Processing: Process presentation files asynchronously using queues or background jobs to prevent blocking the main application thread and maintain responsiveness.
    • Rate Limiting: Implement rate limiting to restrict the number of presentation processing requests from a single user or IP address within a specific timeframe, mitigating abuse.
    • Monitoring and Alerting: Monitor server resource utilization (CPU, memory, disk I/O) and set up alerts to detect unusual spikes during presentation processing, indicating potential DoS attempts.

Threat: XML External Entity (XXE) Injection

  • Description: If PHPOffice/PHPPresentation utilizes XML parsing (especially for PPTX format), and the XML parser is not securely configured, an attacker can inject malicious XML code into a presentation file to perform XXE injection. This allows them to potentially read local files on the server, initiate Server-Side Request Forgery (SSRF) attacks, or trigger a Denial of Service.
  • Impact: Information disclosure (reading sensitive server files), potential SSRF leading to internal network access, and Denial of Service.
  • Affected Component: XML Parsers used internally by PHPOffice/PHPPresentation (if applicable, particularly within PPTX reader).
  • Risk Severity: High
  • Mitigation Strategies:
    • Disable External Entity Processing: Ensure the XML parser used by PHPOffice/PHPPresentation is configured to disable external entity processing. This is a critical security configuration for XML parsing. Verify this setting in the library's configuration or underlying XML handling mechanisms.
    • Regular Updates: Keep PHPOffice/PHPPresentation and its XML parsing dependencies updated to benefit from security patches and best practices in XML handling.

Threat: Zip Archive Extraction Vulnerabilities (Path Traversal)

  • Description: Presentation formats like PPTX are based on ZIP archives. If PHPOffice/PHPPresentation's ZIP extraction process is vulnerable to path traversal attacks, a malicious presentation file could contain ZIP entries with manipulated paths (e.g., "../../../sensitive/file"). When the library extracts this archive, it could write files outside the intended extraction directory, potentially overwriting critical system files or application components.
  • Impact: File system manipulation, potentially leading to application compromise, data corruption, or denial of service.
  • Affected Component: ZIP Archive Handling component within PHPOffice/PHPPresentation, specifically the archive extraction functionality.
  • Risk Severity: High
  • Mitigation Strategies:
    • Secure ZIP Extraction Library: Ensure PHPOffice/PHPPresentation utilizes a secure ZIP extraction library and employs secure practices to prevent path traversal during extraction. Review the library's code or documentation for details on ZIP handling security.
    • Controlled Extraction Directory: When extracting ZIP archives, strictly control and isolate the extraction directory. Verify that the library prevents writing files outside of this designated directory.
    • Regular Updates: Keep PHPOffice/PHPPresentation and its ZIP handling dependencies updated to address any known vulnerabilities in ZIP archive processing.