The Wireless Lan Access Device Security Level Evaluation Technology

With the wide application of wireless local area network(WLAN),the security of WLAN access devices has received more and more attention.Both network operators and device manufacturers are eager to conduct a more comprehensive security level analysis of WLAN access devices to evaluate the security performance of the devices.Existing security level evaluation standards usually adopt attack detection and protection,attack effectiveness evaluation,risk evaluation and other methods,measure the harm degree of vulnerability through attack path,attack effect,asset value and security measures and other elements,and evaluate the network protection ability according to security function requirements.These standards take the network system as the evaluation object,and are affected by the application environment,topology structure,asset value and other factors.As a result,evaluation results of the same security problems in different network system environment are not consistent.So they can not be applied to the security performance evaluation of the network device.On the basis of the existing security evaluation methods,combining with the demand of the state radio monitoring center testing center(SRTC)for the WLAN security performance evaluation,this paper proposes a WLAN access devices security level evaluation framework which integrates security function assessment and vulnerability assessment.Based on the framework,the WLAN access device security performance evaluation system has been designed and implemented.The main work and innovations are as follows:1.A security level evaluation framework for WLAN access devices based on semiquantitative and quantitative analysis methods is proposed to solve the problem that the existing security evaluation results are susceptible to network environment factors.The security level is determined based on the conclusions of security function assessment and vulnerability assessment,and independent of the security of the network environment.The security function evaluation adopts a semi-quantitative evaluation method based on satisfaction degree,and security function requirements are evaluated one by one.The weighted average of the evaluation results can be used to determine if a device meets the requirements for the selected security level.Vulnerability assessment uses a quantitative analysis method based on the Analytic Hierarchy Process(AHP)and a probabilistic model.Firstly,fuzzing test and vulnerability scan are used to detect security vulnerabilities of access devices.Then,the detected security vulnerabilities are weighted using AHP and quantified using the probabilistic model.Finally,according to the weighted average sum of the quantized values,the corresponding vulnerability assessment level is obtained.2.According to the project requirements of SRTC,the security level of WLAN access devices is divided and the security function requirements to be followed are set based on the Common Criteria(CC).According to the product security guarantee capability and the recommended usage scenario,the security level of WLAN access devices is divided.Then,based on the Common Vulnerability Scoring System(CVSS)vulnerability analysis method,the security function requirements under different security levels are set.3.A fuzzing test method for WLAN access devices based on the combination of test case generation and mutation is proposed to solve the problem of poor effectiveness and low test efficiency of test cases in traditional fuzzing methods.To improve the pertinence and effectiveness of test cases,a test case generation method based on generated templates and heuristic test values is used.Generation templates for test cases were constructed for various frames involved in the connection process,and the variation method of each field was identified in the templates.At the same time,a reusable heuristic test case library was created based on the improved depth-first search.In the abnormal state monitoring,for the difficulty that the debuggers to monitor the abnormality can not be used in WLAN access device,a state monitor integrating interactive command,active monitoring,response frame analysis and log analysis is designed to monitor the abnormality of the device,such as minor exception,crash,restart and other abnormal behaviors.Further analysis of response frames can help study how the device handles abnormal test cases.4.Based on the existing research,a prototype of the automatic evaluation system for WLAN security performance is designed and implemented.The system is composed of security function assessment module and vulnerability assessment module,which can realize the security level evaluation function of WLAN access devices.By using the prototype system,this paper evaluates and analyzes WLAN access devices of common brands in the market.The analysis shows that the evaluation system can effectively realize the automatic evaluation of security level of WLAN access devices,and has certain practical value.