Linux用root强制踢掉已登录用户
首先使用w命令查看所有在线用户:
[root@VM_152_184_centos /]# w
20:50:14 up 9 days, 5:58, 3 users, load average: 0.21, 0.05, 0.02
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
root pts/0 101.45.224.253 20:48 0.00s 0.00s 0.00s w
root pts/1 101.45.224.253 20:49 17.00s 0.00s 0.00s -bash
hmj pts/2 101.45.224.253 20:50 2.00s 0.00s 0.00s -bash
执行命令:
pkill -kill -t TTY值
例:踢掉已登录用户hmj
pkill -kill -t pts/2
再用w命令查看是否已经强制踢掉:
[root@VM_152_184_centos /]# w
20:55:10 up 9 days, 6:03, 2 users, load average: 0.03, 0.03, 0.00
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
root pts/0 101.45.224.253 20:48 0.00s 0.00s 0.00s w
root pts/1 101.45.224.253 20:49 5:13 0.00s 0.00s -bash
用fail2ban阻止ssh暴力破解root密码
安装fail2ban工具来实现防暴力破解,防止恶意攻击,锁定恶意攻击IP。
1、如果是centos系统,先yum安装fail2ban
[root@VM_152_184_centos /]# yum -y install fail2ban
2、为了更好的看到有哪些IP在尝试暴利破解,先定义好日志文件路径
[root@VM_152_184_centos /]# cat /etc/fail2ban/fail2ban.conf |grep -v ^#
[Definition]
loglevel = 3
logtarget = SYSLOG //这里是日志路径,可以自定义,比如:/var/log/fail2ban.log
socket = /var/run/fail2ban/fail2ban.sock
pidfile = /var/run/fail2ban/fail2ban.pid
3、自定义主配置文件(当然,也可以不修改,保持默认配置)
[root@VM_152_184_centos /]# cat /etc/fail2ban/jail.conf |grep -v ^# |less
[DEFAULT]
ignoreip = 127.0.0.1/8
bantime = 600 //屏蔽、锁定时间,单位:s
findtime = 600 //600s内尝试登陆失败超过规定次数将被锁定
maxretry = 3 //最大登陆失败次数
backend = auto
usedns = warn
4、最后,启动fail2ban,使其配置生效
[root@VM_152_184_centos /]# service fail2ban start
最后,再查看一下fail2ban日志文件,可以看到已经屏蔽的IP列表(Ban ip是屏蔽/锁定的IP,Unban ip是自动解锁的IP)
[root@VM_152_184_centos /]# cat /var/log/fail2ban.log | grep "ban"
2014-04-15 21:12:18,053 fail2ban.actions: WARNING [ssh-iptables] Ban 198.104.137.151
2014-04-15 21:42:19,037 fail2ban.actions: WARNING [ssh-iptables] Unban 198.104.137.151
2014-04-15 22:12:16,001 fail2ban.actions: WARNING [ssh-iptables] Ban 116.10.191.218
2014-04-15 22:42:16,305 fail2ban.actions: WARNING [ssh-iptables] Unban 116.10.191.218
2014-04-15 23:02:02,609 fail2ban.actions: WARNING [ssh-iptables] Ban 117.34.91.170
2014-04-15 23:26:10,651 fail2ban.actions: WARNING [ssh-iptables] Ban 116.10.191.172
2014-04-15 23:28:02,391 fail2ban.actions: WARNING [ssh-iptables] Ban 198.104.137.151
2014-04-15 23:32:03,428 fail2ban.actions: WARNING [ssh-iptables] Unban 117.34.91.170
2014-04-15 23:46:07,364 fail2ban.actions: WARNING [ssh-iptables] Ban 116.10.191.205
2014-04-15 23:56:10,893 fail2ban.actions: WARNING [ssh-iptables] Unban 116.10.191.172