Insecure Direct Object References (IDOR) are security vulnerabilities that allow attackers to directly access and manipulate sensitive objects or resources without authorization checks in a system's implementation, particularly in Python applications. IDORs can arise when an application provides direct access to objects based on user-supplied input, bypassing authorization mechanisms. Understanding IDOR vulnerabilities is crucial for maintaining the confidentiality, integrity, and availability of sensitive data handled by Python applications. IDORs take different forms depending on application implementation and functionality, including object references, file references, and blind IDORs. Common patterns to help spot IDOR vulnerabilities in code include lack of access control, guessable identifiers, and direct access to files. To fix IDOR vulnerabilities, developers must update the code to have proper access control checks, such as verifying user authorization before accessing sensitive data. Snyk is a security solution that can help identify and fix IDOR vulnerabilities in project dependencies and application code through software composition analysis and static application security testing capabilities. By understanding IDOR vulnerabilities and using tools like Snyk, developers can build secure Python applications that are both performant and reliable.