安装Linux系统调优及安全设置方法

蜗牛vps教程2021-09-143460

1.1 关闭SElinux功能
sed -i '/SELINUX/s/enforcing/disabled/' /etc/selinux/config
setenforce 0
1.2 设定运行级别为3(文本模式)
/etc/inittab
systemctl get-default multi-user.target
1.3 精简开机系统启动 sshd、rsyslog、network、crond、sysstat
centos6：
   LANG=en
   chkconfig --list
   chkconfig --list | grep "3:on" | grep -E "sshd|rsyslog|network|crond|sysstat" | awk '{print "chkconfig " $1 " on"}'| bash
   chkconfig --list | grep "3:on" | grep -vE "sshd|rsyslog|network|crond|sysstat" | awk '{print "chkconfig " $1 " off"}'| bash
centos7：

1.4 关闭iptables防火墙
systemctl stop firewalld.service
systemctl disable firewalld.service

1.5 更改SSH服务器远程登录的配置
Port 52113
UseDNS no
PermitRootLogin yes
PermitEmptyPasswords no
GSSAPIAuthentication no

1.6 利用sudo控制用户对系统命令的使用权限
visudo(/etc/sudoers)
glk All=(All) NOPASSWD:All

1.7 Linux中文显示设置
cat /etc/sysconfg/i18n
echo 'LANG="zh_CN.UTF-8" ' > /etc/sysconfg/i18n

1.8 设置Linux服务器时间同步
/usr/sbin/ntpdate ntp1.aliyun.com
echo "*/5 * * * * /usr/sbin/ntpdate ntp1.aliyun.com &> /dev/null" >> /var/spool/cron/root

1.9 历史记录数和登录超时环境变量设置
1.设置限制账号超时时间 export TMOUT=10
2.设置Linux的命令行的历史记录数 export HISTSIZE=1000
3.历史文件的命令数量变量 export HISTFILESIZE=1000

1.10 调整Linux系统文件描述符数量
查看 ulimit -n
echo "* - nofile 65535" >> /etc/security/limits.conf

1.11 Linux服务器内核参数优化
net.core.rmem_default = 262144
   net.core.rmem_max = 16777216
   net.core.wmem_default = 262144
   net.core.wmem_max = 16777216
   net.core.somaxconn = 262144
   net.core.netdev_max_backlog = 262144
   net.ipv4.tcp_max_orphans = 262144
   net.ipv4.tcp_max_syn_backlog = 262144
   net.ipv4.tcp_max_tw_buckets = 10000
   net.ipv4.ip_local_port_range = 1024 65500
   net.ipv4.tcp_tw_recycle = 1
   net.ipv4.tcp_tw_reuse = 1
   net.ipv4.tcp_syncookies = 1
   net.ipv4.tcp_synack_retries = 1
   net.ipv4.tcp_syn_retries = 1
   net.ipv4.tcp_fin_timeout = 30
   net.ipv4.tcp_keepalive_time = 1200
   net.ipv4.tcp_mem = 786432 1048576 1572864

1.12 定时清理邮件服务器临时目录垃圾文件
centos6:
find /var/spool/postfix/maildrop/ -type f | xargs rm -rf
centos5:
find /var/spool/postfix/clientmqueue/ -type f | xargs rm -rf

1.13 隐藏Linux版本信息
> /etc/issue
> /etc/issue.net

1.14 锁定关键系统文件，防止被提权篡改
上锁命令: chattr +i /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/inittab
解锁命令: chattr -i /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/inittab

1.15 清楚多余的系统虚拟账号
不必要的账号： bin adm lp halt mail uucp operator games gopher ftp dbus vcsa abrt ntp saslauth postfix tcpdump

1.16 为grub菜单加密
1./sbin/grub-md5-crypt生成MD5密码串
2.把密码串放入grub.conf文件splashimage和title之间
password --md5 $1$hoY96$dM9G1bjKLbi/GV8J9neOm1

1.17 禁止Linux系统被ping
内核级禁ping:
   echo "net.ipv4.icmp_echo_ignore_all = 1" > /etc/sysctl.conf
   解除内核级禁ping:
   删除/etc/sysctl.conf中的 "net.ipv4.icmp_echo_ignore_all = 1"，保存后执行以下命令：
   echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all
防火墙级别禁ping:
   iptables -t filter -I INPUT -p icmp -icmp-type 8 -i eth0 -s 192.168.1.0/24 -j ACCEPT

1.18 升级具有典型漏洞的软件版本
rpm -qa openssl openssh bash
yum -y install openssl openssh bash