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计算机网络安全概述

计算机网络安全概述. Q & A. 什么是计算机病毒？ 你遇到过或听说过什么病毒？写出你能想到的和计算机安全相关的关键词 病毒发作会遇到什么样的问题？ 一般如何避免遭到病毒入侵？. What does security mean?. In real life : No one should be able to break into my house Or steal something from me Or impersonate me or others I know Or attack me

uriel-middleton
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计算机网络安全概述

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  1. 计算机网络安全概述

  2. Q & A • 什么是计算机病毒？ • 你遇到过或听说过什么病毒？写出你能想到的和计算机安全相关的关键词 • 病毒发作会遇到什么样的问题？ • 一般如何避免遭到病毒入侵？

  3. What does security mean? • In real life: • No one should be able to break into my house • Or steal something from me • Or impersonate me or others I know • Or attack me • Or take my time with irrelevant things • Or damage my property • ……

  4. What does security mean? • In networks: I want to communicate with A • No one should be able to break into my computer • Or sniff information I exchange • Or spoof my address and act in my name (or somebody else’s) • Or attack me and disable my machine • Or take my resources with bogus packets • Or plant malicious code • Or attack anything on route from me to A • Or misuse my machine to attack someone else • ……

  5. What does security mean? • Goal of networking is to enable communication • At all times and in all scenarios!!! • Security = robustness or fault tolerance? • Security also means keeping communication private

  6. What are the threats? • No one should be able to break into my computer • Hackers • Break password • Misuse vulnerability • Sniff my network • Use social engineering • Impersonate someone I trust • Viruses • Worms（网络）

  7. What are the threats? • No one should sniff the information I exchange • I will use cryptography! • There are many ways to break ciphers • There are many ways to divulge partial information (e.g. who do you talk to) • I would also like to hide who I talk to and when • I will use anonymizationtechniques • Anonymizationhinders other security approaches that build models of normal traffic patterns

  8. What are the threats? • No one should spoof my address or act in my name • I want to be sure who I am talking to (authentication and digital signatures)

  9. What are the threats? • No one should attack me and disable my machine • Denial-of-service attacks （DOS） • Viruses

  10. What are the threats? • No one should take up my resources with bogus • packets • Denial-of-service attacks • Spam mail • Malicious mail • Worms

  11. What are the threats? • No one should plant malicious code on my machine • Viruses • Worms • Denial-of-service attacks (preparatory phase)

  12. What are the threats? • No one should attack anything on route to A • A could be attacked • Routers could be overloaded • DNS （域名解析器） servers could be attacked

  13. What are the threats? • No one should misuse my machine to attack someone else • Zombies • Reflector attacks • Worms • E-mail with viruses • Be a good citizen • …

  14. What are the challenges? • Your security frequently depends on others • Good solution must • Handle the problem to a great extent • Handle future variations of the problem, too • Be inexpensive • Have economic incentive • Require a few deployment points • Require non-specific deployment points

  15. What are the challenges? • Fighting a live enemy • Security is adversarial field • No problem is likely to be completely solved • New advances lead to improvement of attack techniques • Researchers must play double game

  16. What are the challenges? • Attack patterns change • Frequently there is scarce attack data • No agreement about legitimate traffic patterns • No agreement about metrics • There is no standardized evaluation procedure • Some security problems require a lot of resources • to be reproduced realistically

  17. 案例 • 根据360安全中心的统计数据，2010年度网民面临的十大"丢钱"陷阱分别是：购物欺诈网站、股票或彩票欺诈网站、游戏盗号、木马劫持网上交易资金、QQ盗号及借钱诈骗、假冒网银页面钓鱼、网上黑药店、黑客窃取隐私敲诈、虚假中奖信息，以及木马删除重要文件后敲诈"数据恢复费"。

  18. 法国家乐福官方网站被中国黑客攻击，首页写着中国万岁法国家乐福官方网站被中国黑客攻击，首页写着中国万岁 • 提议关闭社会网吧政协委员公司网站被黑 • 2009年黑客入侵花期银行，席卷千万美元引起股票大跌 • 2010年上半年， 59.2%的网民使用网络的过程中遇到了病毒和木马攻击

  19. 典型的网络安全事件 • 1983年 414黑客 6名少年黑客控制60多台电脑 • 1988年 “蠕虫”病毒的发明 罗伯特一莫里斯 造成6000多个系统瘫痪（1/10） 损失1500万-1亿美元 • 1995年 凯文·米特尼克 被称为世界上“头号电脑黑客”闯入多台电脑 偷窃2万个信用卡号和复制软件，曾闯入“北美空中防务指挥系统”；破译“太平洋电话公司”在南加州通信网络的“改户密码”等，损失 8000万美元 • 2000年 雅虎，亚马逊，微软等网络遭到攻击，受害公司损失近10亿美元 • 2003年 “蠕虫王”病毒，利用SQL Server的漏洞进行传播，导致全球范围互联网瘫痪， 经济损失达12亿 • 2007年， 超过9400万用户的visa和mastercard信用卡信息被窃取

  20. 常见的攻击方式 • 病毒 • 木马 • 拒绝服务和分布式拒绝服务攻击 • 欺骗 • 邮件炸弹 • 口令破解 • 社会工程

  21. 攻击工具 • 标注的Tcp/ip工具 • 端口扫描和漏洞扫描 • 网络包分析 • 口令破解工具 • 木马

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