Research on Memory Protection Threat Model of Operating System
|School||National University of Defense Science and Technology|
|Course||Computer Science and Technology|
|Keywords||Threat Model memory protection Petri net Attack Tree MPP model|
Buffer overflow is common software security vulnerability. Malicious users can use the overflow vulnerability of the procedure to attack the target computer systems, or even worse, to control the host system to attack others. The operating system has taken a series of protection mechanisms to the threat of buffer overflow. But as the development of attack technology, these protective mechanisms may be bypassed or compromised. Therefore carries on the modeling to the memory protection mechanism to analyze its vulnerability to be possible further to consummate its function. On the other hand, due to the sensitivity of attack technology, it is less involved in the open literature, resulting in studying on the buffer overflow attacks difficultly, and thus the defense research also failed to introduce effective solution. Therefore, the establishment of the threat model of the memory protection mechanism becomes necessary.We takes the problems and deficiencies of operating system memory protect mechanism and the buffer overflow attack as breakthrough point, takes the threat model as the essential way, and establishes the MPP model based on the Petri net. Carrying on the security evaluation and the analysis to the threat model through the attack tree, this paper memory also researches the protect mechanism formalization analysis method and the buffer overflow attack analysis method. The main work includes:(1)According to the analysis of memory protect mechanism, we proposed a structure method of memory protect mechanism MPP model which is based on Petri net. We discuss the modeling method frame of MPP model. By the analysis of memory protect mechanism and the analysis of Petri net model structure, we abstract the memory protect mechanism and Petri net model to model ontology, and implement the mapping from analysis graph to Petri net model.(2)We use the method of attack tree to mark the threat of buffer overflow, and constitute the attack tree of buffer overflow. Basing on above work, we make the research of buffer overflow risk evaluation method, and propose a suit of risk evaluation method. At last, we constitute the set of attack by using attack tree, and propose an attack tree analysis algorithm which is based on the security of MPP model.(3)Based on the analysis of Windows Vista memory protect mechanism, we constitute the MPP model, and make the frangibility analysis of Windows Vista memory protect mechanism by the MPP model. In the end, we get some shortages of Windows Vista memory protect mechanism. The result validates the validity and correctness of MPP model analysis method.