Linux VPS安装Google Authenticator实现SSH登陆二次验证

by Rat’s

Rat’s Blog / 2019-04-08 20:15

说明:一般我们考虑到VPS的安全问题的时候,都是更改SSH端口和密码,然后更安全的也就是禁用密码使用密匙登录。方法很久前就水过了,这里再分享一个方法,可以在VPS上安装一个Google Authenticator(谷歌身份验证器),这样我们登录VPS的时候,不仅需要密码正确,而且还要你输入正确的动态验证码才能登录进去,这样安全性就高了不少,这里就说下CentOSDebianUbuntu的使用。

提示:教程需要配合Google身份验证器一起使用,手机没有安装该APP的需要安装一下,方便获取动态验证码。   

安装

1、软件包安装

#CentOS 6系统   rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm   yum install google-authenticator -y      #CentOS 7系统   rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm   yum install google-authenticator -y      #Debian/Ubuntu系统   apt update   apt install libpam-google-authenticator -y   

2、编译安装
安装依赖:

#CentOS系统   yum install gcc make pam-devel libpng-devel libtool wget git autoconf automake qrencode -y      #Debian/Ubuntu系统   apt update   apt install -y gcc make autoconf automake libtool libpam0g-dev libqrencode3 git   

安装验证器:

git clone https://github.com/google/google-authenticator-libpam.git   cd google-authenticator-libpam   ./bootstrap.sh   ./configure   make && make install   

配置

1、配置验证器

google-authenticator   

输出如下:

Do you want authentication tokens to be time-based (y/n) y   #验证二维码,在浏览器打开使用谷歌验证器APP扫描添加即可。   https://www.google.com/chart?chs=200x200xxx   Your new secret key is: WKDPJHOKR2P3DOWL   Your verification code is 189192   #临时验证码,手机不在身边可以使用,不过一个码只能用一次   Your emergency scratch codes are:     77678926     14729443     83656478     55669982     23960253      #下面可以直接照着填,或者自己使用谷歌翻译,然后自行选择   Do you want me to update your "/root/.google_authenticator" file (y/n) y      Do you want to disallow multiple uses of the same authentication   token? This restricts you to one login about every 30s, but it increases   your chances to notice or even prevent man-in-the-middle attacks (y/n) y      By default, tokens are good for 30 seconds and in order to compensate for   possible time-skew between the client and the server, we allow an extra   token before and after the current time. If you experience problems with poor   time synchronization, you can increase the window from its default   size of 1:30min to about 4min. Do you want to do so (y/n) y      If the computer that you are logging into isn't hardened against brute-force   login attempts, you can enable rate-limiting for the authentication module.   By default, this limits attackers to no more than 3 login attempts every 30s.   Do you want to enable rate-limiting (y/n) y   

2、配置PAM文件
修改PAM配置文件:

nano /etc/pam.d/sshd   

在相应的位置添加auth required pam_google_authenticator.so代码,大概如下:

#CentOS 6在#%PAM-1.0下面一行添加   #CentOS 7在auth substack password-auth下面一行添加   #Debian和Ubuntu在末尾添加

然后使用Ctrl+xy保存退出。

或者直接使用命令添加:

#CentOS 6系统   sed -i '1aauth required pam_google_authenticator.so' /etc/pam.d/sshd   #CentOS 7系统   sed -i "/auth[ ]*substack[ ]*pass*/aauth required pam_google_authenticator.so" /etc/pam.d/sshd   #Debian/Ubuntu系统   echo 'auth required pam_google_authenticator.so' >>/etc/pam.d/sshd   

如果是编译安装的,还需要做一下软链接:

#CentOS系统   ln -fs /usr/local/lib/security/pam_google_authenticator.so /lib64/security/   #Debian/Ubuntu系统   ln -fs /usr/local/lib/security/pam_google_authenticator.so /lib/x86_64-linux-gnu/security/   

3、修改SSH文件
这里可以直接使用命令:

sed -i -r 's#(ChallengeResponseAuthentication) no#1 yes#g' /etc/ssh/sshd_config   

然后同步下时间:

#查看下服务器时间   date   #如果时区不一样,再使用命令修改为本地时间   ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime   

对于CentOS系统,还需要关闭SELINUX,不过并不是所有系统都是开启状态,使用命令:

#使用命令查看状态   getenforce   #如果输出disabled则为关闭,反之开启,然后使用命令关闭   sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config   

最后重启SSH

#CentOS系统   service sshd restart   #Debian/Ubuntu系统   service ssh restart

配置好了,再登录SSH的时候,这里以Xshell为例,类型选择Keyboard Interactive方式,然后会要你输入动态验证码了。

基本上以后我们每次登录VPS的时候,不仅会要你输入密码,还会要你输入谷歌验证的动态码才能进入VPS,安全增加了不少。

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