Memory Protection Mechanism for NOP Sled Defense
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Solution Overview
Problem
Existing systems are vulnerable to NOP sled attacks, which allow unauthorized access to restricted memory regions by manipulating the CPU's instruction execution flow, posing a security risk.
Innovation Solution
Implementing a mechanism that detects read requests to restricted memory regions and responds with a data value that causes an exception when executed, preventing unauthorized access and execution slides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If read requests to restricted memory regions are allowed, then ease of operation is improved, but security reliability deteriorates due to NOP sled attacks
Solution Approach 1:
The patent applies preliminary anti-action by proactively detecting read requests to restricted memory regions before unauthorized code execution can occur. The memory protection logic identifies suspicious access patterns and prevents NOP sled attacks by blocking access to protected regions, thereby countering potential security threats before they can compromise system reliability while maintaining legitimate memory access operations
2Reliability
If memory protection logic is implemented, then security reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing memory into distinct protected and unprotected regions, allowing selective application of protection mechanisms. The memory protection logic operates independently on specific memory segments, enabling security enforcement without requiring system-wide complexity increases. This modular approach confines the protection logic to only where needed, maintaining overall device simplicity
Solution Approach 2:
The patent introduces memory protection logic as an intermediary layer between the processor and memory regions. This mediator component intercepts and evaluates read requests, determining whether to grant or deny access based on protection status. By positioning this intermediary at the memory interface level, the system achieves enhanced security without significantly complicating the core processor architecture
3Reliability
If read requests are monitored and blocked, then security reliability is improved, but productivity decreases due to access restrictions
Solution Approach 1:
The patent applies preliminary action by pre-configuring memory regions with protection attributes before execution occurs. The memory protection logic has advance knowledge of which regions are protected, allowing it to make immediate allow/deny decisions without requiring complex runtime analysis. This pre-establishment of protection rules enables rapid access decisions that minimize impact on memory access performance while maintaining security
Data Source
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AI summary
The disclosed technology is generally directed to protection against unauthorized code. In one example of the technology, a read request to a restricted region of memory is detected. The read request is associated with a first processor. In response to detecting the read request to the restricted region of memory, a data value that causes an exception in response to execution by the first processor is provided.