|
当服务器遭到黑客攻击时,在多数情况下,黑客可能对系统文件等等一些重要的文件进行修改。对此,我们用Tripwire建立数据完整性监测系统。虽然 它不能抵御黑客攻击以及黑客对一些重要文件的修改,但是可以监测文件是否被修改过以及哪些文件被修改过,从而在被攻击后有的放矢的策划出解决办法。
Tripwire的原理是Tripwire被安装、配置后,将当前的系统数据状态建立成数据库,随着文件的添加、删除和修改等等变化,通过系统数据现状与不断更新的数据库进行比较,来判定哪些文件被添加、删除和修改过。正因为初始的数据库是在Tripwire本体被安装、配置后建立的原因,我们务必应该在服务器开放前,或者说操作系统刚被安装后用Tripwire构建数据完整性监测系统。
|
首先来安装 Tripwire 。
|
[root@sample ~]# wget http://jaist.dl.sourceforge.net/sourceforge/tripwire/tripwire- 100%[====================================>] 1,514,955 02:21:32 (1.28 MB/s) - `tripwire- [root@sample ~]# tar zxvf tripwire- 100%[====================================>] 786,411 164.35K/s ETA 00:00 02:28:50 (154.51 KB/s) - `tw-20030919.patch.gz' saved [786411/786411] [root@sample tripwire- [root@sample tripwire- LICENSE AGREEMENT for Tripwire(R) 2.3 Open Source Please read the following license agreement. You must accept the Press ENTER to view the License Agreement. ← 按回车键阅读协议 Checking for programs specified in install configuration file.... /usr/sbin/sendmail exists. Continuing installation. /bin/vi exists. Continuing installation. ---------------------------------------------- ./bin/siggen found This program will copy Tripwire files to the following directories: TWBIN: /usr/local/sbin CLOBBER is false. Continue with installation? [y/n] y ← 键入y继续安装 /usr/local/sbin: already exists ---------------------------------------------- /usr/local/doc/tripwire/README: copied ---------------------------------------------- Passphrases should be at least 8 characters in length See the Tripwire manual for more information. ---------------------------------------------- (When selecting a passphrase, keep in mind that good passphrases typically Enter the site keyfile passphrase: ← 输入“site keyfile”口令(输入后不会显示),并且记住这个口令 (When selecting a passphrase, keep in mind that good passphrases typically Enter the local keyfile passphrase: ← 输入“local keyfile”口令(输入后不会显示),并且记住这个口令 ---------------------------------------------- ---------------------------------------------- A clear-text version of the Tripwire configuration file ---------------------------------------------- ---------------------------------------------- A clear-text version of the Tripwire policy file ---------------------------------------------- Please refer to /usr/local/doc/tripwire/Release_Notes make[3]: Leaving directory `/root/tripwire- |
|
|
[root@sample ~]# vi /etc/tripwire/twcfg.txt ← 修改文本格式的Tripwire配置文件 |
注:恢复文本格式的Tripwire配置文件,可通过执行“twadmin --print-cfgfile > /etc/tripwire/twcfg.txt”。
[2] Policy文件的配置
Tripwire的数据库是基于Policy文件建立的。但默认的Policy文件并没有有效的依照我们的需要建立数据完整性监测规则,所以这里通过一段Perl脚本来让数据监测实际满足于我们的需要。
|
[root@sample ~]# vi /etc/tripwire/twpolmake.pl ← 建立用于建立Policy文件的Perl脚本 #!/usr/bin/perl open(POL,"$POLFILE") or die "open error: $POLFILE" ; while (<POL>) { [root@sample ~]# perl /etc/tripwire/twpolmake.pl /etc/tripwire/twpol.txt > /etc/tripwire/twpol.txt.out ← 建立Policy文件 |
注:恢复文本格式的Tripwire配置文件,可通过执行“twadmin --print-cfgfile > /etc/tripwire/twcfg.txt”。
[3] 建立数据库
|
[root@sample ~]# tripwire --init ← 建立数据库 |
|
下面开始测试并让Tripwire开始工作。
[1] 建立Tripwire运行脚本:
|
[root@sample ~]# vi tripwire-check ← 建立Tripwire运行脚本 #!/bin/bash PATH=/usr/local/sbin:/usr/bin:/bin # Run the Tripwire # Mail the Tripwire Report to root # Update the Policy File # update the Database |
注:Tripwire的监测报告会被加密保存到/usr/local/lib/tripwire/report目录下。日志被保存在/var/log/messages中。
[2] 测试运行脚本
|
[root@sample ~]# ./tripwire-check ← 运行一次脚本 |
[3] 在服务器本地监测报告的浏览
|
[root@sample ~]# ls -l /usr/local/lib/tripwire/report/ ← 监测报告所在目录的文件列表 Report generated by: root =============================================================================== Host name: sample.centospub.com =============================================================================== ------------------------------------------------------------------------------- Rule Name Severity Level Added Removed Modified Total objects scanned: 17363 =============================================================================== ------------------------------------------------------------------------------- ------------------------------------------------------------------------------- Modified: =============================================================================== ------------------------------------------------------------------------------- ------------------------------------------------------------------------------- Modified object name: /root/tripwire-check Property: Expected Observed |