基于异常控制流识别的漏洞利用攻击检测方法

为应对APT等漏洞利用攻击的问题,提出了一种基于异常控制流识别的漏洞利用攻击检测方法.该方法通过对目标程序的静态分析和动态执行监测,构建完整的安全执行轮廓,并限定控制流转移的合法目标,在函数调用、函数返回和跳转进行控制流转移时,检查目标地址的合法性,将异常控制流转移判定为漏洞攻击,并捕获完整的攻击步骤.实验结果表明,该方法能够准确检测到漏洞利用攻击,并具备良好的运行效率,可以作为漏洞利用攻击的实时检测方案.     

一种基于概率分析的DHR模型安全性分析方法

动态异构冗余(Dynamic Heterogeneous Redundancy,DHR)模型的安全性分析是拟态防御的核心问题之一.本文针对DHR模型安全性量化分析问题提出了执行体-漏洞矩阵和服务体-漏洞矩阵模型,实现了DHR系统的形式化描述.提出了攻击序列法和服务体法的两种计算方法,从系统攻击成功率和被控制率对DHR系统进行安全性分析,推导出非合谋(合谋)盲攻击和非合谋(合谋)最优攻击4种场景下安全性指标的计算公式.通过仿真实验分析了DHR模型各因素对系统安全性的影响,给出了增强DHR系统安全性的具体建议.所提方法能用于DHR系统的安全性量化分析和比较,为DHR系统构建提供量化决策支撑.     

有限异构资源条件下的工业控制拟态调度算法

网络空间拟态防御技术是应对信息系统未知漏洞后门攻击的有效手段,其安全性与执行体的数量、异构化程度以及具体的裁决调度策略紧密相关。然而在工业控制领域,工业应用的生态资源相对封闭,可实现的异构执行体个数受限。针对上述问题,提出一种适用于有限异构资源约束条件下的工业控制拟态调度算法。算法通过引入执行体上线保护寄存器、周期清洗定时器等,能够根据运行环境自适应选择合适的执行体上线,可有效防范N-1模与N模攻击。实验结果表明,所提出的三余度工业控制拟态调度算法,可自适应根据环境特性选择合适的执行体上线,即使在高强度攻击环境下,依然能保持99.24%的高可用概率。     

内生安全增益评估指标度量模型研究

基于拟态防御技术的信息通信技术产品通过引入动态异构冗余,实现对未知漏洞、后门、病毒或木马等威胁的非特异性免疫。为有效评估拟态防御产品的内生安全增益,基于现有拟态防御产品的共性特点,通过研究影响拟态防御产品安全增益的关键要素和属性,提出评估拟态防御产品内生安全增益的评估指标度量模型,为拟态产品开展内生安全增益评估提供参考。     

iOS应用内支付安全分析

应用内支付是开发者盈利的重要手段。然而,由于开发者在具体实现中未对交易进行有效性验证,导致攻击者可以通过控制流劫持和会话劫持两类攻击方式实现免费内购,给开发者权益造成了极大危害。本文以iOS平台应用内支付为研究对象,介绍了其支付流程,分析了支付过程中存在的安全问题及当前存在的攻击方法,最后总结了应用内支付攻击防御思路。     

动态异构冗余结构的拟态防御自动机模型

动态异构冗余结构是拟态防御技术的常用工程模型.然而,目前尚缺乏对该结构实施形式化分析的手段,因为该结构缺乏形式化建模方法.针对此问题,使用有穷状态自动机及其并行组合自动机为一些拟态攻防行为建立计算模型.首先,使用单个有穷状态自动机为单个执行体建模;其次,使用有穷状态自动机的并行组合为执行体组合建模;再次,修改状态迁移规则,得到可描述攻防行为的拟态防御自动机模型;最后,根据该自动机模型的状态条件,分析动态异构冗余结构上拟态攻防行为的安全性.此外,也可使用交替自动机为拟态攻防建模,并把安全性自动分析规约为交替自动机模型检测问题.     

可控内存写漏洞自动利用生成方法

针对现有漏洞自动利用生成方法无法实现从“可控内存写”到“控制流劫持”的自动构造问题,提出一种可控内存写漏洞的自动利用生成方法。首先,基于内存地址控制力度的动态污点分析方法检测可控内存写漏洞;然后,基于漏洞利用模式进行利用要素搜索,通过约束求解自动构造可控内存写漏洞的利用。实验结果表明,所提方法可以有效检测可控内存写漏洞,搜索漏洞利用要素,自动生成从可控内存写到控制流劫持的利用。     

可控内存写漏洞自动利用生成方法

针对现有漏洞自动利用生成方法无法实现从“可控内存写”到“控制流劫持”的自动构造问题,提出一种可控内存写漏洞的自动利用生成方法。首先,基于内存地址控制力度的动态污点分析方法检测可控内存写漏洞;然后,基于漏洞利用模式进行利用要素搜索,通过约束求解自动构造可控内存写漏洞的利用。实验结果表明,所提方法可以有效检测可控内存写漏洞,搜索漏洞利用要素,自动生成从可控内存写到控制流劫持的利用。     

工控系统中PLC安全漏洞及控制流完整性研究

可编程逻辑控制器在工业控制系统中扮演着重要的角色,但近年来公开的PLC安全漏洞却呈现逐年增加的态势.针对PLC开展漏洞防御技术研究,对提高工控系统安全具有重要意义.文中基于控制流完整性,提出了一种针对PLC的控制流完整性防御机制来保护PLC免受漏洞劫持.该防御机制通过检查PLC程序中的控制转移指令,基于插桩技术插入校验...     

拟态计算与拟态安全防御的原意和愿景

以高效能和高安全性计算为目标,提出了以多维重构函数化体系结构与动态多变体运行机制为核心的拟态计算和拟态安全防御技术体系,并对二者的概念和机理从原意和愿景的角度进行了概略介绍,最后给出了需要进一步研究的主要科学与工程技术问题。     

Markov game modeling of mimic defense and defense strategy determination

Network mimic defense technology enhances the robustness of active defense through the redundancy,dynamic and diversity as well as the decision feedback mechanism.However,little work has been done for its security assessment and existing classic game models are not suitable for its dynamic characteristics and lack of universality.A Markov game model was proposed to analyze the transfer relationship between offensive and defensive status and the measurement method of safety and reliability of mimic defense,and calculated the offensive and defensive game equilibrium through non-linear programming algorithm to determine the best defensive strategy considering performance.Experiments give a comparison with the multi-target hiding technique and shows that the mimic defense has a higher defensive effect.Combining with the specific network case,the specific attack and defense path for the exploit of the system vulnerability is given and the effectiveness of the defense strategy algorithm is verified.     

基于贝叶斯攻击图的SDN安全预测方法

现有研究者采用威胁建模和安全分析系统的方法评估和预测软件定义网络（software defined network, SDN）安全威胁,但该方法未考虑SDN控制器的漏洞利用概率以及设备在网络中的位置,安全评估不准确。针对以上问题,根据设备漏洞利用概率和设备关键度结合PageRank算法,设计了一种计算SDN中各设备重要性的算法;根据SDN攻击图和贝叶斯理论设计了一种度量设备被攻击成功概率的方法。在此基础上设计了一种基于贝叶斯攻击图的SDN安全预测算法,预测攻击者的攻击路径。实验结果显示,该方法能够准确预测攻击者的攻击路径,为安全防御提供更准确的依据。     

Evaluation of mimic defense strategy based on M-FlipIt game model

To make up for the lack of security performance evaluation of the mimic defense systems in the advanced persistent threat scenarios an improved game model based on the FlipIt game theory model was proposed.The dynamic strategy of mimic defense under different heterogeneity conditions was evaluated,and a case study for the simulation analysis was conducted.The simulation results show that the rotation of indefinite period can make up for the lack of heterogeneity and maintain the higher game payoff of defenders.     

Mimic defense authentication method for physical access control

To address the security problem of the vulnerability of the authentication methods of traditional physical access control systems,a mimic defense authentication method was designed based on the principle of mimic defense technique and its dynamic heterogeneous redundant architecture (DHR),using mobile 2D code as the interface and dynamic password as the core.First,the actuator pool of the authentication server was constructed.Then,a central controller consisting of functional modules such as input distribution agent,selector and voter was used to dynamically schedule heterogeneous redundant actuators from the actuator pool.Finally,a multimode ruling on the heterogeneous redundant actuator output to determine the authentication result was made by the voter.The experimental results show that the proposed authentication method has higher security and reliability compared to the traditional physical access control system authentication method,and at the same time,it can be used in combination with other authentication methods.     

基于攻防博弈模型的网络安全测评和最优主动防御

文中对攻防博弈模型中的相关内容展开了分析,讨论了攻防博弈模型的网络安全测评要点,包括信息安全测评分析、主动防御系统分析、脆弱性测评分析、防御代价定量分析等,并对攻防博弈模型的最优主动防御要点进行了整理,旨在提高对攻防博弈模型应用价值的认知水平,提升网络安全测评与防御的效果。     

Optimal strategy selection approach of moving target defense based on Markov time game

For the problem that the existed game model was challenging to model the dynamic continuous characteristics of network attack and defense confrontation effectively,a method based on Markov time game was proposed to select the optimal strategy for moving target defense.Based on the analysis of the attack and defense confrontation process of moving targets,the set of moving target attack and defense strategies was constructed.The dynamics of the single-stage moving target defense process was described by time game.The randomness of multi-stage moving target defense state transformation was described by Markov decision process.At the same time,by abstracting the use of resource vulnerability by attack-defense participants as the alternation of the control of the attack surface,the versatility of the game model was effectively guaranteed.On this basis,the existence of equilibrium was analyzed and proved,and the optimal strategy selection algorithm was designed.Finally,the practicality of the constructed model and the effectiveness of the algorithm are verified by an application example.     

Account hijacking threat attack detection for OAuth2.0 authorization API

OAuth2.0 protocol has been widely adopted to simplify user login to third-party applications,at the same time,existing risk of leaking user privacy data,what even worse,causing user accounts to be hijacked.An account hijacking attack model around authorization code was built by analyzing the vulnerabilities of the OAuth2.0 protocol.A vulnerable API identification method based on differential traffic analysis and an account hijacking verification method based on authorized authentication traffic monitoring was proposed.An account hijacking attack threat detection framework OScan for OAuth2.0 authorization API was designed and implemented.Through a large-scale detection of the 3 853 authorization APIs deployed on the Alexa top 10 000 websites,360 vulnerable APIs were discovered.The further verification showed that 80 websites were found to have threat of account hijacking attack.Compared with similar tools,OScan has significant advantages in covering the number of identity provider,the number of detected relying party,as well as the integrity of risk detection.     

基于红蓝对抗的拟态防御体系构建

由于目前网络空间处于攻防不对等的态势，基于“已知风险”的防护体系已经无法满足日益严峻的攻击压力，需要构建一种可以对“未知风险”进行防护且有一定自适应能力的安全架构。本文通过将红蓝对抗经验引入到安全防护体系的建设中，以网站防护为例，研究了构建基于拟态防御的安全架构模型，提出将自适应防护能力集合到安全工作的方法，从而提高了信息系统对未知威胁攻击的防护能力。