1、漏扫发现存在OpenSSH命令注入漏洞（CVE-2020-15778）因为目前版本过低，根据综合评估需要将openssh升级为8.8P1版本。

2、无法采取yum安装的方式，需要使用编译安装。

3、需要资料包

zlib-1.2.11.tar.g

openssh-8.8p1.tar.gz

openssl-1.0.2o.tar.gz

4、更改yum源（主要是为了安装telnet服务，升级过程中ssh会关闭）

[[email protected] ~]# vim /etc/yum.repos.d/centos75.repo

[centos75]
name=centos75
baseurl=http://XXXXXXX/cen75/   ##内网yum源
gpgcheck=0
enabled=1

5、[[email protected] ~]# yum clean all

[[email protected] ~]# yum list

[[email protected] ~]# yum -y install xinetd telnet-server

[[email protected] ~]# systemctl start telnet.socket

[[email protected] ~]# useradd test

[[email protected] ~]# echo "abc123" | passwd --stdin test

6、[[email protected] ~]# yum -y install gcc make perl zlib zlib-devel pam pam-devel

[[email protected] ~]# rpm -qa | egrep "gcc|make|perl|zlib|zlib-devel|pam|pam-devel"

7、使用telnet登陆

telnet XX.XX.XX.XX,用户名使用创建的账户test，密码abc123

[[email protected] ~]$ su - root ##输入root密码切换到root用户

8、将下载好的资料包上传，

9、[[email protected] ~]#  systemctl stop sshd

[[email protected] ~]#  cp -r /etc/ssh /etc/ssh.old 

[[email protected] ~]#  rpm -qa | grep openssh

[r[email protected] ~]#  rpm -e --nodeps openssh-7.4p1-16.el7.x86_64
[[email protected] ~]#  rpm -e --nodeps openssh-clients-7.4p1-16.el7.x86_64
[[email protected] ~]#  rpm -e --nodeps openssh-server-7.4p1-16.el7.x86_64
[[email protected] ~]#  rpm -qa | grep openssh

10.找到存放资料包的目录，安装zlib-1.2.11

[[email protected] ~]tar -xzvf zlib-1.2.11.tar.gz

[[email protected] ~] cd zlib-1.2.11

[[email protected] ~] ./configure --prefix=/usr/local/zlib

[[email protected] ~] make

[[email protected] ~]make install

[[email protected] ~]ll /usr/local/zlib
[[email protected] ~]vi /etc/ld.so.conf.d/zlib.conf

[[email protected] ~]ldconfig -v
[[email protected] ~]tar -xzvf openssl-1.0.2o.tar.gz

[[email protected] ~] cd openssl-1.0.2o

11、找到存放资料包的目录，安装openssl-1.0.2o

[[email protected] ~]tar -xzvf openssl-1.0.2o.tar.gz

[[email protected] ~]cd openssl-1.0.2o

[[email protected] ~] ./config shared zlib

[[email protected] ~] make

[[email protected] ~]make install

[[email protected] ~]mv /usr/bin/openssl /usr/bin/openssl.bak

[[email protected] ~]ln -s /usr/local/ssl/bin/openssl /usr/bin/openssl

[[email protected] ~] ln -s /usr/local/ssl/include/openssl /usr/include/openssl

[[email protected] ~]vi /etc/ld.so.conf.d/ssl.conf

 [[email protected] ~] ldconfig -v

[[email protected] ~]openssl version -a

12、找到存放资料包的目录安装openssh-8.8p1

[[email protected] ~]tar -zxvf openssh-8.8p1.tar.gz

[[email protected] ~]cd openssh-8.8p1

[[email protected] ~]./configure --prefix=/usr --sysconfdir=/etc/ssh --with-zlib --without-openssl-header-check --with-ssl-dir=/usr/local/ssl --with-privsep-path=/var/lib/sshd

[[email protected] ~]make

[[email protected] ~]chmod 600 /etc/ssh/ssh_host_rsa_key
[[email protected] ~]chmod 600 /etc/ssh/ssh_host_ecdsa_key
[[email protected] ~]chmod 600 /etc/ssh/ssh_host_ed25519_ke
[[email protected] ~]chmod 600 /etc/ssh/ssh_host_ed25519_key

[[email protected] ~]make install

[[email protected] ~]ssh -V

[[email protected] ~]echo "PasswordAuthentication yes"   >> /etc/ssh/sshd_config
[[email protected] ~]echo "PermitRootLogin yes" >> /etc/ssh/sshd_config
[[email protected] ~]cp -p contrib/redhat/sshd.init /etc/init.d/sshd
[[email protected] ~]chmod +x /etc/init.d/sshd

[[email protected] ~]chkconfig --add sshd
[[email protected] ~]chkconfig sshd on
[[email protected] ~]systemctl restart sshd

13、删除建立的telnet账号和密码，关闭telnet服务

[[email protected] ~]systemctl stop telnet.socket
[[email protected] ~]userdel test