Session State Validation for CSRF Mitigation
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Solution Overview
Problem
Conventional methods to mitigate Cross-Site Request Forgery (CSRF) attacks, such as using the referrer header and cryptographic signing, are inadequate due to spoofing vulnerabilities and high cryptographic processing overhead, respectively, making them unreliable for large-scale electronic environments.
Innovation Solution
Systems and methods validate the source of submissions by utilizing session or state information stored on both client and server sides, ensuring that session IDs are securely stored and accessed only within the origin context, preventing unauthorized submissions by prompting users for confirmation through interstitial pages when invalid state information is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryptographic signing with random numbers is used to prevent CSRF attacks, then security against unauthorized submissions is improved, but cryptographic processing overhead increases significantly
Solution Approach 1:
The patent extracts the security verification function from complex cryptographic operations and relocates it to simple session state comparison. Instead of using cryptographic signatures, the system uses session IDs and state information that are already stored on the server, eliminating the need for expensive cryptographic processing while maintaining security.
Solution Approach 2:
The patent replaces expensive cryptographic operations with cheap, simple session state comparisons. The session IDs and state information are stored in memory and can be quickly compared without requiring cryptographic processing, making the security mechanism computationally inexpensive and scalable.
2Device complexity
If referrer header is used to determine request source, then implementation complexity is reduced, but reliability decreases due to spoofing vulnerabilities
Solution Approach 1:
The patent introduces session state information as an intermediary between the client and server authentication mechanism. Instead of relying on the referrer header that can be spoofed, the system uses session IDs and state information that are securely stored on the server and cannot be easily manipulated by clients, thereby improving reliability while maintaining simplicity.
3Ease of operation
If client-side control of referrer header is allowed, then ease of operation is improved, but security against spoofing decreases
Solution Approach 1:
The patent inverts the traditional CSRF mitigation approach by instead of relying on client-controlled headers that can be spoofed, it uses server-side session state verification. The server compares session IDs and state information to determine the legitimate source of requests, thereby eliminating spoofing vulnerabilities while maintaining client control flexibility.
Data Source
AI summary
Cross Site Request Forgery (CSRF) and other types of fraudulent submission can be mitigated using state information that typically is already maintained for various users. Each submission requiring authentication can include a state identifier (ID). The state ID can be compared to a corresponding secure state ID stored in a secure location, such as in a secure token or cookie or in a variable on a page that can only be accessed by code executing in the same security context as the site to which the request is made. If the received state ID is valid and matches the secure state ID, the submission is processed. Otherwise, an interstitial element is generated to prompt the user to confirm the prior submission. A subsequent confirmation submission confirming the prior submission and containing the proper state ID can be processed. If no such confirmation is received, the submission is not processed.