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I黑客攻击与防范技术论文姓名:学号:年级:院系:专业:完成时间:I摘要:在网络信息时代的今天,网络安全问题日趋严重,黑客攻防技术成为当今网络技术关注和发展的焦点,随着网络的发展,网络安全问题已经成为一个被人们强烈关注的热点。而其中黑客攻击所造成的安全问题是很重要的一个方面。本文将介绍网络安全面临的主要威胁,重点分析黑客攻击的一般步骤,使用的手段,以及解决应对的最新方法手段。关键词:网络安全威胁黑客攻击步骤原理对策1目录摘要···································································································I关键词···································································································I1.黑客常见攻击步骤····························································································21.1攻击前奏····················································································21.2实施攻击····················································································31.3巩固控制····················································································31.4巩固控制····················································································32.常见的几种攻击分类·············································································32.1缓冲区溢出攻击··········································································32.2欺骗类攻击·················································································32.3对防火墙的攻击··········································································42.4利用病毒攻击·············································································42.5木马程序攻击·············································································43.常见的攻击························································································43.1DOS攻击····················································································43.1DOS攻击原理··············································································53.1Trinoo攻击软件攻击实例······························································54.常见的网络安全防范措施······································································84.1网络级安全检测与防范·································································84.2及时备份重要数据·······································································84.3使用加密机制传输数据·································································84.4网络攻击的攻击软件:PasswordCrackers········································95.结语·································································································96.参考文献·························································································102黑客攻击与防范技术对于互联网网络安全问题,必须谈的一个话题就是黑客(Hacker)。黑客是英文Hacker的英文译音,它起源于美国麻省理工学院的计算机实验室中。是指对计算机某一领域有着深入的理解,并且十分热衷于潜入他人计算机、窃取非公开信息的人。每一个对互联网络的知识十分了解的人,都有可能成为黑客。黑客是:“喜欢探索软件程序奥秘,并从中增长其个人才干的人。”显然,“黑客”一语原来并没有丝毫的贬义成分,直到后来,少数怀有不良的企图,利用非法手段获得的系统讯问权去闯入运程机器系统、破坏重要数据,或为了自己的私利而制造麻烦的具有恶意行为的人慢慢玷污了“黑客”的名声,“黑客”才逐渐演变成入侵者、破坏者的代名词。1.黑客常见攻击步骤:黑客常用的攻击步骤可以说变幻莫测,但纵观其整个攻击过程,还是有一定规律可循的,一般可以分:攻击前奏、实施攻击、巩固控制、继续深入几个过程。见下图1示:1.1攻击前奏黑客锁定目标、了解目标的网络结构,收集各种目标系统的信息等。锁定目标:网络上有许多主机,黑客首先要寻找他找的站点的。当然能真正标识主机的是IP地址,黑客会利用域名和IP地址就可以顺利地找到目标主机,了解目标的网络结构:确定要攻击的目标后,黑客就会设法了解其所在的网络结构,哪里是网关、路由,哪里有防火墙,哪些主机与要攻击的目标主机关系密切等,最简单地就是用tracert命令追踪路由,也可以发一些数据包看其是否能通3过来猜测其防火墙过滤则的设定等。当然老练的黑客在干这些的时候都会利用别的计算机来间接的探测,从而隐藏他们真实的IP地址。收集系统信息:在收集到目标的第一批网络信息之后,黑客会对网络上的每台主机进行全面的系统分析,以寻求该主机的安全漏洞或安全弱点。首先黑客要知道目标主机采用的是什么操作系统什么版本,如果目标开放telnet服务,那只要telnetxx.xx.xx.xx.(目标主机),就会显示“digitalunlx(xx.xx.xx.)(ttypl)login:”这样的系统信息。接着黑客还会检查其开放端口进行服务分析,看是否有能被利用的服务。1.2实施攻击当黑客探测到了足够的系统信息,对系统的安全弱点有了了解后就会发动攻击,当然他们会根据不同的网络结构、不同的系统情况而采用的不同的攻击手段。1.3巩固控制黑客利用种种手段进入目标主机系统并获得控制权之后,进行破坏活动,删除数据、涂改网页等。为了能长时间表的保留和巩固他对系统的控制权,不被管理员发现,他会做两件事:清除记录和留下后门。1.4继续深入清除日志、删除拷贝的文件等手段来隐藏自己的踪迹之后,攻击者就开始下一步的行动;窃取主机上的各种敏感信息:软件资料、客户名单、财务报表、信用卡号等等。2.常见的几种攻击分类:2.1缓冲区溢出攻击通过往程序的缓冲区写超出其长度的内容,造成缓冲区的溢出,从而破坏程序的堆栈,使程序转而执行其它的指令,如果这些指令是放在有root权限的内存中,那么一旦这些指令得到了运行,黑客就以root权限控制了系统,达到入侵的目的。缓冲区攻击的目的在于扰乱某些以特权身份运行的程序的功能,使攻击者获得程序的控制权。缓冲区溢出的一般攻击步骤为:在程序的地址空间里安排适当的代码(植入法或利用已存在的代码),然后,通过适当的地址初始化寄存器和存储器,让程序跳到黑客安排的地址空间中执行(如激活纪录、函数指针或长跳转缓冲区等)。2.2欺骗类攻击TCP/IP协议本身的一些缺陷可以被利用,使黑客可以对TCP/IP网络进行攻击,网络欺骗的技术主要有:HoneyPot和分布式HoneyPot、欺骗空间技术等。主要方式有:IP欺骗;ARP欺骗;DNS欺骗;Web欺骗;电子邮件欺骗;4以IP欺骗攻击为例说明如下,其的实施步骤为:选定目标主机——发现主机间的信任模式——使被信任主机葬失工作能力——TCP序列号的取样和预测——冒充被信任主机进入系统,并留下后门供以后使用。2.3对防火墙的攻击一般来说,防火墙的抗攻击性很强,可是它也不是不可攻破的。其实,防火墙也是由软件和硬件组成的,在设计和实现上都不可避免地存在着缺陷。对防火墙的探测攻击技术有:Firewalking技术、Hping。绕过防火墙认证的攻击手法有:地址欺骗和TCP序号协同攻击、IP分片攻击、Tcp/Ip会话劫持、协议隧道攻击、干扰攻击、利用FTP-pasv绕过防火墙认证的攻击。直接攻击防火墙系统的常见手法有:CiscoPix防火墙的安全漏洞:CiscoPIX防火墙的拒绝服务漏洞、CISCOPIX防火墙FTP漏洞允许非法通过防火墙。2.4利用病毒攻击病毒是黑客实施网络攻击的有效手段之一,它具有传染性、隐蔽性、寄生性、繁殖性、潜伏性、针对性、衍生性、不可预见性和破坏性等特性,而且在网络中其危害更加可怕,目前可通过网络进行传播的病毒已有数万种,可通过注入技术进行破坏和攻击。计算机病毒攻击的传播途径有电子邮件、传统的软盘、光盘、BBS、浏览、FTP文件下载、新闻组、点对点通信系统和无线通信系统等。2.5木马程序攻击特洛依木马是一种骗子程序,提供某些功能作为诱饵,背地里干一些鬼事,当目标计算机启动时,木马程序随之启动,然后在某一特定的端口监听,在通过监听端口收到命令后,木马程序根据命令在目标计算机上执行一些操作,如传送或删除文件,窃取口令,重新启动计算机等。常见的特洛伊木马程序有:BO、Netspy、Netbus等。3.常见的攻击:3.1DoS攻击DoS攻击的方式主要是利用合理的服务请求,来占用过多的网络带宽和服务器资源,致使正常的连接请求无法得到响应。常见的DoS攻击方法有:SYNFlood攻击、Land攻击、Smurf攻击、UDP攻击等。下图2为DoS攻击的基本过程。53.2DDoS攻击原理DDoS主要采用了比较特殊的3层客户机/服务器结构,即攻击端、主控端和代理端,这3者在攻击中各自扮演着不同的角色。攻击者:攻击者所用的计算机是攻击主控台,可以是网络上的任何一台主机,甚至可以是一个活动的便携机。攻击者操纵整个攻击过程,它向主控端发送攻击命令。主控端:主控端是攻击者非法侵入并控制的一些主机,这些主机还分别控制大量的代理主机。主控端主机的上面安装了特定的程序,因此它们可以接受攻击者发来的特殊指令,并且可以把这些命令发送到代理主机上。代理端:代理端同样也是攻击者侵入并控制的一批主机,它们上面
本文标题:黑客攻击与防范技术论文
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