SSH 配置
vim /etc/ssh/sshd_config <<VIM > /dev/null 2>&1
:s/#LoginGraceTime 2m/LoginGraceTime 2m/
:s/#PermitRootLogin yes/PermitRootLogin no/
:s/#MaxAuthTries 6/MaxAuthTries 3/
:%s$#AuthorizedKeysFile$AuthorizedKeysFile /dev/null$
:%s/GSSAPIAuthentication yes/GSSAPIAuthentication no/
:%s/GSSAPICleanupCredentials yes/GSSAPICleanupCredentials no/
:wq
VIM
禁止证书登陆 AuthorizedKeysFile /dev/null
锁定用户禁止登陆
passwd -l bin
passwd -l daemon
passwd -l adm
passwd -l lp
passwd -l sync
passwd -l shutdown
passwd -l halt
passwd -l mail
passwd -l uucp
passwd -l operator
passwd -l games
passwd -l gopher
passwd -l ftp
passwd -l nobody
passwd -l vcsa
passwd -l saslauth
passwd -l postfix
检查可以登陆的用户与有密码的用户
#!/bin/bash
function section(){
local title=$1
echo "=================================================="
echo " $title "
echo "=================================================="
}
section "Check login user"
grep -v nologin /etc/passwd
section "Check login password"
grep '\$' /etc/shadow
section "Check SSH authorized_keys file"
for key in $(ls -1 /home)
do
if [ -e $key/.ssh/authorized_keys ]; then
echo "$key : $key/.ssh/authorized_keys"
else
echo "$key : "
fi
done
55.2.1. pam_tally2.so
此模块的功能是，登陆错误输入密码3次，5分钟后自动解禁，在未解禁期间输入正确密码也无法登陆。
在配置文件 /etc/pam.d/sshd 顶端加入
auth required pam_tally2.so deny=3 onerr=fail unlock_time=300
查看失败次数
# pam_tally2 Login Failures Latest failure From root 14 07/12/13 15:44:37 192.168.6.2 neo 8 07/12/13 15:45:36 192.168.6.2
重置计数器
# pam_tally2 -r -u root Login Failures Latest failure From root 14 07/12/13 15:44:37 192.168.6.2 # pam_tally2 -r -u neo Login Failures Latest failure From neo 8 07/12/13 15:45:36 192.168.6.2
pam_tally2 计数器日志保存在 /var/log/tallylog 注意，这是二进制格式的文件
例 55.1. /etc/pam.d/sshd
# cat /etc/pam.d/sshd #%PAM-1.0 auth required pam_tally2.so deny=3 onerr=fail unlock_time=300 auth required pam_sepermit.so auth include password-auth account required pam_nologin.so account include password-auth password include password-auth # pam_selinux.so close should be the first session rule session required pam_selinux.so close session required pam_loginuid.so # pam_selinux.so open should only be followed by sessions to be executed in the user context session required pam_selinux.so open env_params session optional pam_keyinit.so force revoke session include password-auth
以上配置root用户不受限制, 如果需要限制root用户，参考下面
auth required pam_tally2.so deny=3 unlock_time=5 even_deny_root root_unlock_time=1800
55.2.2. pam_listfile.so
用户登陆限制
将下面一行添加到 /etc/pam.d/sshd 中，这里采用白名单方式，你也可以采用黑名单方式
auth required pam_listfile.so item=user sense=allow file=/etc/ssh/whitelist onerr=fail
将允许登陆的用户添加到 /etc/ssh/whitelist，除此之外的用户将不能通过ssh登陆到你的系统
# cat /etc/ssh/whitelist neo www
例 55.2. /etc/pam.d/sshd - pam_listfile.so
# cat /etc/pam.d/sshd #%PAM-1.0 auth required pam_listfile.so item=user sense=allow file=/etc/ssh/whitelist onerr=fail auth required pam_tally2.so deny=3 onerr=fail unlock_time=300 auth required pam_sepermit.so auth include password-auth account required pam_nologin.so account include password-auth password include password-auth # pam_selinux.so close should be the first session rule session required pam_selinux.so close session required pam_loginuid.so # pam_selinux.so open should only be followed by sessions to be executed in the user context session required pam_selinux.so open env_params session optional pam_keyinit.so force revoke session include password-auth
sense=allow 白名单方式, sense=deny 黑名单方式
auth required pam_listfile.so item=user sense=deny file=/etc/ssh/blacklist onerr=fail