一个Linux系统安全设置的Shell脚本的分享（适用CentOS）
我们将常用的系统安全配置制作为一个shell脚本，只需要在服务器上运行这个shell脚本即可完成安全设置。
linux的系统安全设 置shell脚本是第二次更新，已经大量应用在某大型媒体网站体系中，加入了之前没有想到的一些安全设置。使用方法将其复制，保存为一个shell文件， 比如security.sh.将其上传到linux服务器上，执行sh security.sh，就可以使用该脚本了！
# desc: setup linux system security
#account setup
passwd -l xfs
passwd -l news
passwd -l nscd
passwd -l dbus
passwd -l vcsa
passwd -l games
passwd -l nobody
passwd -l avahi
passwd -l haldaemon
passwd -l gopher
passwd -l ftp
passwd -l mailnull
passwd -l pcap
passwd -l mail
passwd -l shutdown
passwd -l halt
passwd -l uucp
passwd -l operator
passwd -l sync
passwd -l adm
passwd -l lp
# chattr /etc/passwd /etc/shadow
chattr +i /etc/passwd
chattr +i /etc/shadow
chattr +i /etc/group
chattr +i /etc/gshadow
# add continue input failure 3 ,passwd unlock time 5 minite
sed -i 's#auth required pam_env.so#auth required pam_env.sonauth required pam_tally.so onerr=fail deny=3 unlock_time=300nauth required /lib/security/$isa/pam_tally.so onerr=fail deny=3 unlock_time=300#' /etc/pam.d/system-auth
# system timeout 5 minite auto logout
echo "tmout=300" >>/etc/profile
# will system save history command list to 10
sed -i "s/histsize=1000/histsize=10/" /etc/profile
# enable /etc/profile go!
source /etc/profile
# add syncookie enable /etc/sysctl.conf
echo "net.ipv4.tcp_syncookies=1" >> /etc/sysctl.conf
sysctl -p # exec sysctl.conf enable
# optimizer sshd_config
sed -i "s/#maxauthtries 6/maxauthtries 6/" /etc/ssh/sshd_config
sed -i "s/#usedns yes/usedns no/" /etc/ssh/sshd_config
# limit chmod important commands
chmod 700 /bin/ping
chmod 700 /usr/bin/finger
chmod 700 /usr/bin/who
chmod 700 /usr/bin/w
chmod 700 /usr/bin/locate
chmod 700 /usr/bin/whereis
chmod 700 /sbin/ifconfig
chmod 700 /usr/bin/pico
chmod 700 /bin/vi
chmod 700 /usr/bin/which
chmod 700 /usr/bin/gcc
chmod 700 /usr/bin/make
chmod 700 /bin/rpm
# history security
chattr +a /root/.bash_history
chattr +i /root/.bash_history
# write important command md5
cat > list << "eof" && /bin/ping /bin/finger /usr/bin/who /usr/bin/w /usr/bin/locate /usr/bin/whereis /sbin/ifconfig /bin/pico /bin/vi /usr/bin/vim /usr/bin/which /usr/bin/gcc /usr/bin/make /bin/rpm eof for i in `cat list` do if [ ! -x $i ];then echo "$i not found,no md5sum!" else md5sum $i >> /var/log/`hostname`.log
fi
done
rm -f list