Misconfigured XML
Return to Serialization Frameworks, Java
Don't Return to Misconfigured Serialization Frameworks, Misconfigured Serialization Settings, Misconfigured Serialization Settings, Misconfigured Logging of Deserialization Errors
TLDR: Misconfigured XML, introduced in 1998 by the W3C, can lead to vulnerabilities such as XXE (XML External Entity attacks), denial of service (DoS), and data leakage. These issues stem from insecure parsing configurations, improper validation, and inadequate restrictions on XML features, violating several OWASP Top Ten principles, including Input Validation, Access Controls, and secure Error Handling.
Improper input validation during XML parsing can allow attackers to inject malicious XML content. Without validation, attackers can exploit entities or inject harmful payloads, leading to unauthorized actions or data tampering. Strict Input Validation practices mitigate these risks and comply with OWASP Top Ten recommendations.
https://owasp.org/www-community/Input_Validation
One of the most severe risks of misconfigured XML is XXE attacks, where external entities in XML files are resolved, enabling attackers to access sensitive files, exfiltrate data, or execute remote code. Disabling external entity resolution and using safe XML libraries align with secure deserialization principles in the OWASP Top Ten.
https://owasp.org/www-community/vulnerabilities/XML_External_Entity_(XXE)_Processing
Allowing the use of DTDs (Document Type Definitions) and entities without restrictions can lead to resource consumption attacks, such as the Billion Laughs Attack, causing DoS by overwhelming system resources. Disabling DTD processing ensures compliance with OWASP Top Ten's focus on resource management.
https://owasp.org/www-community/Denial_of_Service
Exposing XML files containing sensitive information without encryption can lead to data leakage. Encrypting sensitive elements or ensuring encrypted transport (e.g., TLS) protects against unauthorized access and aligns with OWASP Top Ten's Data Encryption best practices.
https://owasp.org/www-community/Data_Encryption
Improper Error Handling in XML parsers can inadvertently reveal internal system details, such as stack traces or schema paths, to attackers. Following secure Error Handling practices ensures that error messages are generic and do not disclose sensitive application details.
https://owasp.org/www-community/Error_Handling
Over-reliance on default configurations in XML parsers can expose applications to attacks. Many Framework Defaults prioritize compatibility over security. Customizing parser settings to disable unsafe features is critical to meeting OWASP Top Ten standards.
https://owasp.org/www-community/Framework_Security_Project
Logging raw or malformed XML data without sanitization increases the risk of exposing sensitive information. Following secure Logging practices, such as masking sensitive fields and encrypting logs, ensures compliance with OWASP Top Ten security standards.
https://owasp.org/www-community/Logging_and_Monitoring_Cheat_Sheet
Improper CORS configurations for XML APIs can result in unauthorized cross-domain access. Enforcing strict origin policies and validating requests ensures compliance with OWASP Top Ten's Policy Enforcement principles.
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
Neglecting regular dependency updates for XML libraries exposes applications to vulnerabilities in outdated components. Employing alerts for vulnerable components and conducting dependency checking mitigates risks associated with legacy parsers.
https://owasp.org/www-project-dependency-check/
Failing to implement size limits or restricting recursion depth for XML files can make applications vulnerable to denial of service attacks. Setting strict limits on file size and processing depth aligns with OWASP Top Ten recommendations for secure resource handling.