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📁 一份很好的linux入门资料
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<HTML><HEAD>  <TITLE>BBS水木清华站∶精华区</TITLE></HEAD><BODY><CENTER><H1>BBS水木清华站∶精华区</H1></CENTER>发信人:&nbsp;<A HREF="mailto:SoC.bbs@bbs.cs.nthu.edu.tw">SoC.bbs@bbs.cs.nthu.edu.tw</A>&nbsp;(牵线人),&nbsp;看板:&nbsp;Plan&nbsp;<BR>标&nbsp;&nbsp;题:&nbsp;Re:&nbsp;谈谈系统安全&nbsp;<BR>发信站:&nbsp;清华资讯系学会(枫桥驿站)&nbsp;(Fri&nbsp;Sep&nbsp;&nbsp;6&nbsp;23:33:57&nbsp;1996)&nbsp;<BR>转信站:&nbsp;sob!news.cs.nthu!maple&nbsp;<BR>&nbsp;<BR>在巩固了&nbsp;sendmail&nbsp;(port&nbsp;25)之後,&nbsp;接下来,&nbsp;要继续攘&nbsp;<BR>外的大业,&nbsp;安装&nbsp;tcp-wrapper&nbsp;及&nbsp;logdaemon.&nbsp;<BR>&nbsp;<BR>一个开放的系统,&nbsp;最令人担忧的,&nbsp;就是敌暗我明,&nbsp;和毫不&nbsp;<BR>设防.&nbsp;而&nbsp;tcp-wrapper&nbsp;和&nbsp;logdaemon&nbsp;的安装,&nbsp;就是要达&nbsp;<BR>成限制连线和记载连线的功能,&nbsp;如此,&nbsp;管理者只要每天流&nbsp;<BR>览记录档(可利用&nbsp;loghost&nbsp;的设定将,&nbsp;记录档集中至某一&nbsp;<BR>台,&nbsp;甚至还可以用&nbsp;console&nbsp;printer&nbsp;直接输出),&nbsp;就可以&nbsp;<BR>对连线状况有清楚的了解,&nbsp;也可对可疑的尝试连线,&nbsp;防□&nbsp;<BR>於未然.&nbsp;<BR>&nbsp;<BR>tcp-wrapper&nbsp;和&nbsp;logdaemon&nbsp;记录的是连进的资料,&nbsp;如果&nbsp;<BR>行有馀力,&nbsp;还可更改&nbsp;logdaemon&nbsp;的&nbsp;source,&nbsp;把使用的&nbsp;<BR>tty&nbsp;和离线的时间也记录下来,&nbsp;如此可取代&nbsp;utmp&nbsp;的功能,&nbsp;<BR>万一遭到不测&nbsp;HD&nbsp;被清光时,&nbsp;可从&nbsp;log&nbsp;中看出,&nbsp;事发的&nbsp;<BR>可能时间,&nbsp;当时还在线上的使用者,&nbsp;如何连线,&nbsp;来自何方.&nbsp;<BR>&nbsp;<BR>在进行安装&nbsp;tcp-wrapper&nbsp;时,&nbsp;应同时检视&nbsp;/etc/inetd.conf&nbsp;<BR>的内容,&nbsp;将不必要,&nbsp;多馀的&nbsp;service&nbsp;关闭.&nbsp;对一个纯&nbsp;BBS,&nbsp;<BR>不上&nbsp;YP,&nbsp;不做&nbsp;NFS,&nbsp;那就除了留下&nbsp;telnet&nbsp;(bbs&nbsp;和&nbsp;管&nbsp;<BR>理用),&nbsp;都可以全关了.&nbsp;在一般情况下,&nbsp;除了特定加入的&nbsp;<BR>service&nbsp;(如:&nbsp;snp,&nbsp;pop,&nbsp;samba,&nbsp;ident)&nbsp;和&nbsp;ftp,&nbsp;shell,&nbsp;<BR>login,&nbsp;talk(?),&nbsp;finger(?),&nbsp;rquota/1(NFS&nbsp;quota&nbsp;on)外,&nbsp;<BR>其他的也可以关了.&nbsp;对&nbsp;BBS&nbsp;管理用的&nbsp;port,&nbsp;则应用&nbsp;tcpd&nbsp;<BR>最小□围的开放连线.&nbsp;方便往往是安全的最大敌人.&nbsp;<BR>&nbsp;<BR>其他&nbsp;default&nbsp;在&nbsp;inetd.conf&nbsp;的&nbsp;service,&nbsp;如&nbsp;walld/1,&nbsp;<BR>用简单的方法,&nbsp;就可以为&nbsp;BBS/一般工作站&nbsp;带来&nbsp;&quot;惊喜&quot;.&nbsp;<BR>&nbsp;<BR>当然,&nbsp;如果您在&nbsp;/etc/inetd.conf&nbsp;看到不明的&nbsp;entry,&nbsp;如:&nbsp;<BR>ingres&nbsp;&nbsp;stream&nbsp;&nbsp;tcp&nbsp;nowait&nbsp;&nbsp;root&nbsp;&nbsp;&nbsp;&nbsp;/bin/sh&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sh&nbsp;-i&nbsp;<BR>那麽恭喜您,&nbsp;您已经和他人共享&nbsp;root&nbsp;权限了&nbsp;!!&nbsp;<BR>&nbsp;<BR>改好,&nbsp;重叫&nbsp;inetd&nbsp;之後,&nbsp;顺便检查一下&nbsp;/.rhosts,&nbsp;<BR>/etc/hosts.equiv&nbsp;是否有可爱&nbsp;&quot;+&quot;&nbsp;出现在其中,&nbsp;顺便再&nbsp;<BR>看看&nbsp;/etc/rc*&nbsp;中,&nbsp;有没有不明的&nbsp;daemon&nbsp;在开机时,&nbsp;就&nbsp;<BR>已经被启动了.&nbsp;<BR>&nbsp;<BR>如果有任何迹象显示,&nbsp;已经和他人共用&nbsp;root,&nbsp;那一切就得&nbsp;<BR>重头来过了.&nbsp;<BR>&nbsp;<BR>Summary:&nbsp;1.&nbsp;安装&nbsp;tcp-wrapers_7.4,&nbsp;logdeamon-5.3&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.&nbsp;检查设定&nbsp;/etc/inetd.conf&nbsp;(syslog.conf)&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.&nbsp;检查&nbsp;/.rhosts,&nbsp;/etc/hosts.equiv,&nbsp;/etc/rc*&nbsp;<BR>&nbsp;<BR>待续....&nbsp;<BR>--&nbsp;<BR>※&nbsp;Origin:&nbsp;枫桥驿站(bbs.cs.nthu.edu.tw)&nbsp;◆&nbsp;From:&nbsp;alpha4&nbsp;<BR><CENTER><H1>BBS水木清华站∶精华区</H1></CENTER></BODY></HTML>
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