使用chkrootkit工具保护服务器

安装chkrootkit,你可以自己去 http://www.chkrootkit.org/download/ 下载源码包,然后自己编译,也可以和我一样偷懒用别人做好的二进制包.

centos 下用非官方源安装chkrootkit:

首先添加dag 源for centos(我的系统是centos5.2).

vi /etc/yum.repos.d/dag.repo
[dag]
name=Dag RPM Repository for Red Hat Enterprise Linux
baseurl=http://apt.sw.be/redhat/el$releasever/en/$basearch/dag
gpgcheck=1
enabled=1

rpm –import http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt

yum 安装chkrootkit:

yum update
yum install chkrootkit

chkrootkit的应用:

chkrootkit 的使用非常简单直接运行 chkrootkit 命令,然后会有如下输出:

ROOTDIR is `/'
Checking `amd'… not found
Checking `basename'… not infected
Checking `biff'… not found
Checking `chfn'… not infected
Checking `chsh'… not infected
Checking `cron'… not infected
Checking `crontab'… not infected
Checking `date'… not infected
Checking `du'… not infected
Checking `dirname'… not infected
Checking `echo'… not infected
Checking `egrep'… not infected
Checking `env'… not infected

如果有rootkit会报"INFECTED" 所以可以直接用chkrootkit -n|grep 'INFECTED'更直接一些.

定时检测并在出问题时给管理员发邮件.
创建如下脚本chkrootkit.sh并放入crontab 定时运行.

cat chkrootkit.sh
#!/bin/bash
PATH=/usr/bin:/bin
TMPLOG=`mktemp`
# Run the chkrootkit
/usr/bin/chkrootkit > $TMPLOG
# Output the log
cat $TMPLOG | logger -t chkrootkit
# bindshe of SMTPSllHow to do some wrongs
if [ ! -z "$(grep 465 $TMPLOG)" ] &&
[ -z $(/usr/sbin/lsof -i:465|grep bindshell) ]; then
sed -i '/465/d' $TMPLOG
fi
# If the rootkit have been found,mail root
[ ! -z "$(grep INFECTED $TMPLOG)" ] &&
grep INFECTED $TMPLOG | mail -s "chkrootkit report in `hostname`" root

chmod 700 chkroot.sh
mv chkrootkit /etc/cron.daily

这样系统会每天运行chkrootkit 检测系统,并在检测到rootkit 时给root 发一封邮件.