attack-surface.md

Attack Surface Analysis for pocoproject/poco

Attack Surface: XML External Entity (XXE) Injection

• Description: An attacker can inject malicious XML code that references external entities. When parsed by a vulnerable XML parser, it can lead to information disclosure, Denial of Service (DoS), or Server-Side Request Forgery (SSRF).
• Poco Contribution: Poco's Poco::XML::DOMParser and related XML parsing components can be vulnerable if not configured to disable external entity processing.
• Example: An application using Poco::XML::DOMParser parses XML data from user input. An attacker sends XML containing an external entity definition pointing to a local file (<!DOCTYPE foo [ <!ENTITY xxe SYSTEM "file:///etc/passwd" > ]><foo>&xxe;</foo>). The parser, if vulnerable, will attempt to read and potentially expose the contents of /etc/passwd.
• Impact: Confidentiality breach (information disclosure), DoS, SSRF.
• Risk Severity: High
• Mitigation Strategies:
  • Disable External Entity Processing: Configure Poco::XML::DOMParser to disable external entity resolution and processing. Consult Poco documentation for specific settings to disable XXE (often involves setting parser features or using secure parsing options).
  • Input Sanitization: Sanitize or validate XML input to remove or neutralize potentially malicious external entity declarations.
  • Use SAX Parser (if applicable): Consider using a SAX parser instead of DOM parser if full DOM functionality is not required, as SAX parsers are often less susceptible to XXE by default.

Attack Surface: HTTP Request Smuggling

• Description: Exploiting discrepancies in how front-end proxies and back-end servers parse HTTP requests. Attackers can "smuggle" requests to the back-end server, bypassing security controls or gaining unauthorized access.
• Poco Contribution: Poco's HTTP server components (Poco::Net::HTTPServer, Poco::Net::HTTPRequestHandler) might be vulnerable if they don't strictly adhere to HTTP specifications or if there are inconsistencies in request parsing compared to front-end proxies.
• Example: An attacker crafts a malicious HTTP request with ambiguous Content-Length and Transfer-Encoding headers. A front-end proxy might interpret the request differently than the Poco-based back-end server. This allows the attacker to prepend a malicious request to a legitimate request, causing the back-end server to process the smuggled request as if it were part of the legitimate one.
• Impact: Authentication bypass, unauthorized access, data manipulation, cache poisoning.
• Risk Severity: High
• Mitigation Strategies:
  • Strict HTTP Compliance: Ensure Poco HTTP server configuration and application logic strictly adhere to HTTP specifications, especially regarding request parsing and header handling.
  • Standardized Infrastructure: Use well-tested and hardened front-end proxies and load balancers that are known to have robust HTTP request parsing.
  • Disable Ambiguous Features: Disable or carefully configure HTTP features that can lead to ambiguities in request parsing (e.g., chunked transfer encoding if not strictly necessary).
  • Regular Security Audits: Conduct regular security audits focusing on HTTP request handling logic and potential smuggling vulnerabilities.

Attack Surface: Path Traversal

• Description: An attacker manipulates file paths provided by users to access files or directories outside of the intended scope, potentially gaining access to sensitive data or system files.
• Poco Contribution: Poco's file system functionalities (Poco::File, Poco::Path) are used to interact with the file system. If applications use these functionalities with user-controlled input without proper sanitization, path traversal vulnerabilities can arise.
• Example: An application uses Poco::File to serve files based on user-provided filenames. An attacker provides a filename like ../../../../etc/passwd. If the application doesn't properly validate and sanitize the path, it might access and serve the /etc/passwd file instead of files within the intended directory.
• Impact: Confidentiality breach (sensitive file access), potential code execution if combined with other vulnerabilities.
• Risk Severity: High
• Mitigation Strategies:
  • Input Validation and Sanitization: Strictly validate and sanitize user-provided file paths. Use allow-lists of permitted characters and paths.
  • Canonicalization: Canonicalize paths using Poco::Path::canonical() to resolve symbolic links and relative paths, making it harder for attackers to bypass path restrictions.
  • Chroot Environment (if applicable): In highly sensitive applications, consider using a chroot environment to restrict the application's file system access to a specific directory.
  • Principle of Least Privilege: Run the application with minimal file system permissions necessary.

Attack Surface: Deserialization Vulnerabilities (Custom Serialization with Poco::RemotingNG)

• Description: If an application uses custom serialization/deserialization mechanisms, particularly with complex frameworks like Poco::RemotingNG, vulnerabilities in the deserialization process can allow attackers to execute arbitrary code by crafting malicious serialized data.
• Poco Contribution: Poco::RemotingNG provides a framework for remote procedure calls and serialization. If custom serialization logic within RemotingNG is not carefully implemented, it can introduce deserialization vulnerabilities.
• Example: An application uses Poco::RemotingNG with custom serialization for complex objects. An attacker crafts a malicious serialized object that, when deserialized by the application, exploits a vulnerability in the custom deserialization code to execute arbitrary commands on the server.
• Impact: Remote Code Execution (RCE), complete system compromise.
• Risk Severity: Critical
• Mitigation Strategies:
  • Avoid Custom Serialization if Possible: Prefer using well-established and secure serialization formats and libraries whenever possible.
  • Secure Deserialization Practices: If custom serialization is necessary, implement secure deserialization practices. Validate data integrity (e.g., using digital signatures) before deserialization.
  • Input Validation: Validate the structure and content of serialized data before deserialization to detect and reject potentially malicious payloads.
  • Regular Security Audits: Thoroughly audit custom serialization and deserialization code for potential vulnerabilities.
  • Principle of Least Privilege: Run the application with minimal privileges to limit the impact of potential RCE.

Attack Surface: Buffer Overflows in Socket Handling

• Description: Writing data beyond the allocated buffer size in socket operations can lead to memory corruption, crashes, or potentially Remote Code Execution.
• Poco Contribution: Poco's Sockets library provides low-level socket APIs. If developers using these APIs don't carefully manage buffer sizes and data lengths when receiving or sending data, buffer overflows can occur.
• Example: An application uses Poco::Sockets::StreamSocket to receive data into a fixed-size buffer. If the received data exceeds the buffer size and the application doesn't perform proper bounds checking, a buffer overflow can occur, potentially overwriting adjacent memory regions.
• Impact: Denial of Service (crash), potential Remote Code Execution (RCE).
• Risk Severity: High
• Mitigation Strategies:
  • Bounds Checking: Always perform thorough bounds checking when reading data into buffers from sockets. Ensure that the amount of data read does not exceed the buffer's capacity.
  • Use Safe APIs: Utilize safer APIs provided by Poco or the underlying operating system that automatically handle buffer management and prevent overflows (if available and suitable).
  • Memory Safety Tools: Use memory safety tools (e.g., AddressSanitizer, Valgrind) during development and testing to detect buffer overflows and other memory-related errors.
  • Code Reviews: Conduct code reviews to identify potential buffer overflow vulnerabilities in socket handling code.