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安全与可信security and trusted
脆弱性安全 vs. 结构性安全Vulnerability vs. Structure攻防两端如何在结构性安全环境中寻求空间Space in the structural environment
潘柱廷(大潘) Jordan Panhttp://blog.jordanpan.cn
mailto:[email protected]
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摘要Summary
• 脆弱性安全Vulnerability-oriented security• 结构性安全Structural security• 结构性安全中的脆弱性
Vulnerabilities in structures• 结构性威胁Structural threats
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脆弱性安全Vulnerability-oriented security
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脆弱性Vulnerabilities
• 弱口令 simple password• 病毒 virus• 操作系统漏洞 OS flaw• 协议漏洞 protocol flaw• 造成拒绝服务攻击的性能限制
performance limitation• 防火墙配置不当 bad configuration of firewalls• … …
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面向脆弱性的安全Vulnerability-oriented security
• 防病毒系统 anti-virus system• 漏洞扫描系统 vulnerability scanner• 补丁管理系统 patch management system• 入侵检测系统 IDS• 防拒绝服务攻击系统 anti-DoS• 防火墙 Firewall• 多功能安全网关 UTM• … …
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PSPC需求驱动筐架
Requirement Driven BaCaMeth
需求筐架
Req.BCM.来自内部
From Internal来自外部
From External
主动引导
Active体系化
Systematic政策性
Policy
被动要求
Passive问题型
Problem合规性
Compliance
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面向脆弱性的风险管理Vulnerability-oriented risk management
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国家标准中的风险管理关系图Risk management elements in Chinese standard
使命Mission
脆弱性Vulnerability
安全需求Requirement
安全措施Safeguard
资产价值Asset value
资产Asset
威胁Threat
风险Risk
残余风险Residual R.
事件Event
依赖
On
拥有Have
被满
足Sa
tisfie
d by
抗击 Resist
利用
暴露Explore
降低Reduce
increase
增加Increase
增加Increase
导出Lead
演变
成O
ccur
未被满足 not satisfied by
未控制Uncontrolled
可能诱发Invoke
残留
Leave
成本
Cos
t
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最精简的风险管理３要素模型3-element risk management model
三要素风险管理模型
资产和业务 保障措施 威胁
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2006 SC Awards• Best anti-malware solution
– Best Anti-spyware– Best Anti-trojan– Best Anti-virus – Best Anti-worm
• Best Content Security Solution – Best Anti-spam – Best Email Content Filtering – Best Email Security – Best IM security – Best Intellectual Property Protection
• Best Network Security Solution – Best Wireless Security – Best Enterprise Firewall – Best Intrusion Detection – Best Intrusion Prevention – Best Desktop Firewall
• Best Remote Access – Best VPN - SSL – Best VPN - Ipsec– Best Endpoint Security Solution – Best Web Filtering – Best Encryption
• Best Identity Management Solution – Best Password Management – Best Authentication – Best Single Sign-on – Best Two-Factor Solution
• Best Unified Threat Solution – Best Integrated Security Software – Best Integrated Security Appliance – Best Managed Security Service – Best Email Managed Service
• Best Network Security Management – Best Event Management – Best Computer Forensics – Best Policy Management – Best Security Audit – Best Security Management Tool
• Best Vulnerability Assessment and Remediation
– Best Patch Management – Best Vulnerability Assessment
Source from: http://www.scmagazine.com/uk/awards/previous/26104/year/2006/
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脆弱性安全的产业环境Vulnerability-oriented security industrial environment
威胁方Threat agents
厂商Provider
用户User
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木桶原理的迷失Misleading of Cask Rule
• 误导– 将整体结构仅仅简化为防御结构
– 不考虑防御纵深问题
– 只考虑静态的结果状态
– 没有成本观念
– … …
• Misleading– Only consider prevention structure– Not consider deep prevention– Only consider static state– Not consider cost-effective– … …
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结构性安全Structural security
基本结构basic structure紧密结构 tight structure松散结构loose structure
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访问控制的RM机制Reference monitor of access control
• 访问控制的RM机制是非
常基本的安全结构
• Reference monitor of access control is a very basic security structure
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RM机制有效的结构性条件Structural conditions of valid RM mechanism
• 三个条件
– 不能被绕过
– 不可篡改
– 足够小，可以被证明
• 3 conditions of VRM– Can not be bypass– Can not be tampered– Be small enough, can
be proved
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Randomly GeneratedSymmetric Key (seed + PRNG)
AlicePublickey
Privatekey
Private key
Public key
Bob
密钥交换过程Key Exchange Process
messagemessage
X15/^ow83h7ERH39DJ3H
messagemessage
X15/^ow83h7ERH39DJ3H
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紧密安全结构的代表——可信计算Tight security structure — Trusted Computing
http://www.trustedcomputinggroup.org
• 可信的定义 Definition of trust– 可信就是，一个设备的行为是按照其预期目标和指定方式执行的
Trust is the expectation that a device will behave in a particular manner for a specific purpose.
– 一个可信平台应当至少提供三个基本特性：保护能力、完整性测量和完整性报告
A trusted platform should provide at least three basic features:protected capabilities, integrity measurement and integrity reporting.
(From section 4.1, TCG Architecture Overview 1.0)
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TCG的基石性原理Fundamental rule of TCG
• 信任根就像“公理”一样，是信任的基础。在PC系统中，常常用硬件芯片实现。
• Roots of trust– In TCG systems roots of trust are components that
must be trusted because misbehavior might not be detected.
• 信任链则是信任传递的机制。常常采用密码技术。
• Chains of trust– Transitive trust also known as “Inductive Trust”,
is a process where the Root of Trust gives a trustworthy description of a second group of functions.
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一个包含TPM的PCReference PC platform containing a TCG TPM
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TCG – 可信平台模块TCG – Trusted Platform Module (TPM)
• 一个可信平台常常拥有三个可信根
There are commonly three Roots of Trust in a trusted platform– 测量可信根 root of trust for measurement (RTM)– 存储可信根 root of trust for storage (RTS) – 报告可信根 root of trust for reporting (RTR)
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证明协议和消息交换Attestation protocol and message exchange
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TPM – 存储可信根的体系结构TPM – Root of Trust for Storage (RTS)
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TPM 部件体系结构TPM component architecture
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TCG 软件分层TCG software layering
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可信平台的生命周期The trusted platform lifecycle
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可信平台上的用户认证User authentication using trusted platforms
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可信平台上的用户认证User authentication using trusted platforms
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经典的四角模型The classical four corners model
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四角模型的可信平台实现Detailed TP deployment architecture
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TCG对于可信计算平台的划分8 categories of Trusted platform
体系结构体系结构ArchitectureArchitecture
移动设备移动设备MobileMobile
TPMTPM
客户端客户端PC ClientPC Client
服务器服务器ServerServer
软件包软件包Software StackSoftware Stack
存储存储StorageStorage可信网络连接可信网络连接
Trusted Network ConnectTrusted Network Connect
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TCG的IWG和TNC的对应关系the IWG and TNC architecture
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TNC体系结构TNC architecture
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TNC体系结构下的消息流Message flow between components
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拥有TPM的TNC体系结构The TNC architecture with the TPM
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思科的自防御网络体系Cisco’s self-defending network
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松散安全结构的代表——框架和方案Loose security structure — Framework
• 松散结构中的各个部件关联关系，常常靠人的集成来实现
The connection among the components of loose structure is always integrated by human.
• 松散结构常常表现为框架Framework– 技术框架Technology framework– 管理体系Management system
• ISO27001, ISO20000, etc.
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技术功能是PDR的衍生PDR can express technology framework
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检测能力是松散技术结构的关联要素Detection make the loose structure tight
• 攻击者不得不面对越来越多的
Attackers have to face more– 入侵检测 IDS– 漏洞扫描 scanner– 应用审计系统 Application auditing system– 日志系统 log system– 蜜罐 honey pot– 取证系统 forensic system– 监控平台 monitoring platform– 等等 etc.
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一个信息安全管理体系的结构Structure of a ISMS (modified ISO27001)
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结构性安全中的脆弱性Vulnerabilities in structures
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你对刚才阐述的结构性安全有什么感觉？What’s your feeling about structural security?
• 复杂 complex• 怀疑其完备性 concern about the completion• 成本 cost• 蠢人永远有 stupid guys are there• … …
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不要被“结构性安全”给忽悠了！Do not be misled by structural security
• 不要被“结构性安全”给忽悠了！脆弱性安全和结
构性安全并不是对立的，也不是两个发展阶段；脆弱性安全也有结构，结构性安全也有脆弱性。
• Do not be misled by structural security– Vulnerability-oriented security also has structure– Structural security also has vulnerabilities
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借助非技术环节来侵害技术结构Find vulnerabilities from non-technology parts
Randomly GeneratedSymmetric Key (seed + PRNG)
AlicePublickey
Privatekey
Private key
Public key
Bob
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借助非技术环节来侵害技术结构Find vulnerabilities from non-technology parts
Randomly GeneratedSymmetric Key (seed + PRNG)
AlicePublickey
Privatekey
Private key
Public key
Bob Private key
Public key
Carl
线路的透明插入，可以完成对于加密通信的嗅探攻击
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借助非技术环节来侵害技术结构Find vulnerabilities from non-technology parts
Randomly GeneratedSymmetric Key (seed + PRNG)
AlicePublickey
Privatekey
Private key
Public key
Bob Private key
Public key
Carl
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结构性安全的局限性Limitation of structural security
• 结构是在环境中的、有边界的
environment and boundary
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在生命周期中寻找弱点Find vulnerabilities along the lifecycle
• 厂家的生产环节常常会埋有后门
back doors embedded during manufacturing• 没有一个系统是完美的
No perfect system• … …
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在结构的时序中寻找突破Find vulnerabilities through time sequence
• 以文档保密系统为例
Sample: Document protection system• 文档的生成环节最可能存在漏洞
Vulnerabilities during creating documentation
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结构性安全的局限性Limitation of structural security
• 结构是在环境中的、有边界的
environment and boundary• 在不同阶段、不同人手中保持安全很困难
different phases and organizations
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在人性中寻找弱点Find vulnerabilities from human behavior
• 社交工程攻击Social Engineering• 隐私保护Privacy protection• 自由倾向Anti-DRM• 懒惰Lazy• … …
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结构性安全的局限性Limitation of structural security
• 结构是在环境中的、有边界的
environment and boundary• 在不同阶段、不同人手中保持安全很困难
different phases and organizations• 人把科学变成了艺术
Human transform science to art
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结构本身可能就有问题Find vulnerabilities from structure itself
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• 对于AR/PEP/PDP的伪装，可能打破整个结构
every role may be spoofed• 所有看似漂亮的结构，其性能和可用性问题可能会非常严重，会轻易被拒绝服务攻击击垮
Most beautiful structures have performance and availability problems and may be easy to be kick down by DoS.
• 那么多传统攻击方式，可能有的还有效
Some traditional attacks are still effective
结构本身可能就有问题Find vulnerabilities from structure itself
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结构性安全还要继续博弈We are still in the game
• 怎么博弈？
How to Play the game?– 你了解对方的结构吗？
Do you know the structure of all players?– 你了解对方了解多少自己的结构吗？
Do you know “how much have the other player known about your structure” ?
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结构性威胁Structural threats
知识、资源和原则
Knowledge, Resources and Principles
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知识Knowledge
• 寻求对于系统更深层次技术结构的研究
Who know lower?• 寻求对于系统宏观结构的了解
Who know the macro-structure better?• 寻求对于具体对象的全面了解
How many details do you know?• … …
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资源Resources
• 从分布式拒绝服务攻击到僵尸网络，掌握具有结构和组织的攻击体
Botnet is a sample of structural software organization for attacking
• 在时序上组成结构，非常有利于攻击
Time sequence spreading is a good thinking of structural attack
• … …
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结构的一些关键字Key words of structure
• Business• Distribution• Hierarchy• Time sequence• Life-cycle• Management
– Organization– Regular– Process Control
• Value
• 业务• 分布式• 层次• 时序• 生命周期• 管理
– 组织– 制度– 过程控制
• 价值
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流程化的结构思路Process-oriented structure
processprocess
inputinput outputoutput
Process ownerProcess owner
operatoroperator
InfraInfra--structurestructure
KnowledgeKnowledgebasebase
LOGLOGArchiveArchive
ProcessProcessimprovingimproving
MonitorMonitor
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原则Principles
• 安全没有百分之百 No 100% Security• 安全相对性的三个原则 3 security relativity rule
–生存原则 survival rule
–风险原则 Risk rule
–保镖原则 bodyguard rule自身完备性要求
Perfective requirement
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总结 Conclusion
• 脆弱性安全Vulnerability-oriented security• 结构性安全Structural security• 结构性安全中的脆弱性
Vulnerabilities in structures• 结构性威胁Structural threats
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总结：一个可以持续研究下去的课题Conclusion: A good problem to keep approaching
脆弱性防御V.O. defend
结构性防御Structural
defend
脆弱性攻击V.O. attack
结构性攻击Structural
attack
脆弱性和结构性 Vulnerability-oriented vs. structural
攻击和防守
defe
nd v
s. a
ttack
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谢谢…Thanks…
大潘 Jordan Pan
