CSRF Detection via HTTP Traffic Mutation and Replay

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Solution Overview

Problem

Current security tools are inadequate in detecting Cross-Site Request Forgery (CSRF) vulnerabilities, as they rely on unsupervised blackbox testing and static source code analysis, which are insufficient for identifying complex HTTP request dependencies and authentication-dependent state changes, leading to false positives and negatives.

Innovation Solution

A system that monitors and analyzes HTTP traffic and server-side changes to identify potential CSRF candidates by decomposing requests into semantic components, performing value mutation operations, and replaying HTTP requests to assess exploitability, using inter-trace analysis and virtualized server-side platforms to validate vulnerabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If unsupervised blackbox testing and static source code analysis are used, then the detection process is simple, but the detection accuracy is low leading to false positives and negatives

Engineering Contradiction:
ImproveCSRF detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection system is divided into multiple specialized modules: HTTP traffic monitoring component, server-side change detection component, candidate decomposition module, mutation operation module, and validation module. Each module handles a specific aspect of CSRF detection, allowing complex analysis while maintaining manageable system architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary validation mechanism that acts as a bridge between initial candidate identification and final vulnerability confirmation. This intermediary layer performs mutation operations and replay testing to filter false positives, improving accuracy without requiring the entire system to be overly complex.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If static source code analysis is used, then the detection process is fast, but it cannot identify complex HTTP request dependencies and authentication-dependent state changes

Engineering Contradiction:
Improvevulnerability detection reliabilityVSAvoiddetection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary decomposition of HTTP requests into semantic components before actual vulnerability testing. By pre-analyzing request structures, identifying parameters, and categorizing state changes beforehand, the system prepares data for faster and more reliable mutation testing without redundant processing during the critical validation phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The detection approach transitions from static analysis to dynamic monitoring by observing actual HTTP traffic and server-side state changes during runtime. This dynamic approach allows the system to identify authentication-dependent state changes and complex dependencies that only manifest during actual application execution, improving reliability.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If all suspect candidate requests are analyzed without filtering, then no false positives are missed, but the validation process becomes inefficient and resource-intensive

Engineering Contradiction:
Improvefalse positive eliminationVSAvoidvalidation efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Instead of performing complete validation on all suspect requests, the system applies partial validation through targeted mutation operations on specific semantic components of each request. By focusing mutation testing on critical parameters identified during decomposition, the system achieves sufficient false positive elimination without the excessive resource consumption of exhaustive validation.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system changes parameters of suspect requests through systematic mutation operations, modifying individual parameters to test whether changes affect server-side state. This parameter-focused approach allows efficient filtering of false positives by identifying which parameter changes actually trigger vulnerable state changes, rather than analyzing entire requests in full detail.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10505966B2Cross-site request forgery (CSRF) vulnerability detection
Publication Date: 2019.12.10 SAP SE
  • US10505966B2 patent drawing
  • US10505966B2 patent drawing
  • US10505966B2 patent drawing

AI summary

Embodiments detect cross-site request forgery (CSRF) attacks by monitoring, mutation, and analysis of suspect requests that are received by an application server. An engine observes UI interaction, HTTP traffic, and server-side changes in order to create an initial list of CSRF candidates (e.g., HTTP requests that could indicate a CSRF vulnerability). Embodiments may feature a virtualized server-side platform including sensors deployed for application persistence monitoring. Using inter-trace analysis, these CSRF candidates are de-composed into their semantic components (e.g., parameter values and classes). By performing value mutation operations on these components and repeated replay of the resulting HTTP requests, CSRF candidates are tested to see if the underlying HTTP request could be utilized in the context of a CSRF attack. Subsequent validation and exploitability assessment may reduce the initial list of suspect candidate requests to only those exploitable cases for which a proof-of-vulnerability demonstration exploit can be created.