Linux安全配置杂文

文章由LinuxBoy分享于2019-03-24 04:03:46热评（417）

Linux安全配置杂文

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

Java代码

#!/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)

if [ -e $key/.ssh/authorized_keys ]; then

echo "$key : $key/.ssh/authorized_keys"

else

echo "$key : "

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

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

root 14 07/12/13 15:44:37 192.168.6.2

# pam_tally2 -r -u neo

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

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