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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:jordan@venustech.com.cn

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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

Sat

isfi

ed b

y

抗击 Resist

利用

暴露Explore

降低Reduce

增加incre

ase增加

Increase

增加Increase

导出Lead

演变成

Occur

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3-element risk management model

资产和业务Asset

保障措施Safeguard

威胁Threat

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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)

Alice

Publickey

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”, i

s 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

TPMTPM

移动设备移动设备 MobileMobile 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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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)

PHY 环境与设备

POL 方针和策略

NET 网络与通信

SYS 主机与系统

APP 应用与业务

DAT 数据/文档/介质

RSK 风险管理

BCM 业务连续性管理

ENG项目工程

OPR 运行与维护

ORG人员和组织

CPL合规性

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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)

Alice

Publickey

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)

Alice

Publickey

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)

Alice

Publickey

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

Infra-Infra-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

def

end

vs.

atta

ck

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谢谢…Thanks…

大潘 Jordan Pan