原因是现有版本存在安全漏洞，需要升级到新版本

原有版本和升级后的版本

OpenSSL 1.0.2k-fips  26 Jan 2017
->
OpenSSL 1.1.1w  11 Sep 2023OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
->
OpenSSH_9.5p1, OpenSSL 1.1.1w  11 Sep 2023

查看现有版本

# 查看系统版本
# cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)# 查看OpenSSL版本
# openssl version
OpenSSL 1.0.2k-fips  26 Jan 2017# 查看OpenSSH版本
# ssh -V
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017

安装 telnet

防止因卸载OpenSSH而导致无法登录主机

# 安装 telnet
yum -y install telnet telnet-server# 启动 telnet
systemctl enable telnet.socketsystemctl is-enabled telnet.socketsystemctl start telnet.socket# 关闭安全文件
mv /etc/security /etc/security.bak

确认openssh升级成功，连接无异常后卸载telnet服务

systemctl stop telnet.socketsystemctl disable telnet.socket# 升级完毕后，开启安全文件
mv /etc/security.bak /etc/securityyum -y remove telnet telnet-server

安装OpenSSH依赖包

yum -y install gcc keyutils-libs rpm-build krb5-devel libcom_err-devel libselinux-devel pam-* openssl-devel pkgconfig vsftpd zlib*

下载安装包

https://www.openssl.org/source/old/

https://www.openssh.com/portable.html#downloads

安装OpenSSL

wget https://www.openssl.org/source/old/1.1.1/openssl-1.1.1w.tar.gztar -zxvf openssl-1.1.1w.tar.gzcd openssl-1.1.1w./config shared --prefix=/usr/local/openssl-1.1.1wmake && make install# 检查安装情况
/usr/local/openssl-1.1.1w/bin/openssl version
OpenSSL 1.1.1w  11 Sep 2023

安装OpenSSH

wget https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-9.5p1.tar.gztar -zxvf openssh-9.5p1.tar.gzcd openssh-9.5p1./configure --prefix=/usr/local/openssh-9.5p1 --with-ssl-dir=/usr/local/openssl-1.1.1wmake && make install# 检查安装情况
/usr/local/openssh-9.5p1/sbin/sshd -V
OpenSSH_9.5p1, OpenSSL 1.1.1w  11 Sep 2023

修改配置（重要）

# /usr/local/openssh-9.5p1/etc/sshd_config
# 允许root以密码的方式登录
PermitRootLogin yes

开机自启

# /usr/lib/systemd/system/sshd9.service
[Unit]
Description=OpenSSH server daemon
After=network.target[Service]
Type=simple
Environment=LD_LIBRARY_PATH=/usr/local/openssl-1.1.1w/lib
ExecStart=/usr/local/openssh-9.5p1/sbin/sshd -D -f /usr/local/openssh-9.5p1/etc/sshd_config
ExecReload=/bin/kill -HUP $MAINPID
KillMode=process
Restart=on-failure
RestartSec=42s[Install]
WantedBy=multi-user.target

停止原sshd服务

systemctl stop sshd.servicesystemctl disable sshd.service

备份sshd

mkdir /home/ssh-old-bak
mv /etc/ssh /home/ssh-old-bak/
mv /usr/sbin/sshd /home/ssh-old-bak/
mv /usr/lib/systemd/system/sshd-keygen.service /home/ssh-old-bak/
mv /usr/lib/systemd/system/sshd.service /home/ssh-old-bak/
mv /usr/lib/systemd/system/sshd@.service /home/ssh-old-bak/
mv /usr/lib/systemd/system/sshd.socket /home/ssh-old-bak/

启动新版本sshd9服务

systemctl daemon-reload
systemctl start sshd9.service
systemctl status sshd9.service
systemctl enable sshd9.service

问题和解决办法

问题1：openssl 查看version出现报错

# 执行查看版本的时候，提示 libssl.so.1.1 找不到
/usr/local/openssl-1.1.1w/bin/openssl version/usr/local/openssl-1.1.1w/bin/openssl: error while loading shared libraries: libssl.so.1.1: cannot open shared object file: No such file or directory## 解决办法
ln -s /usr/local/openssl-1.1.1w/lib/libssl.so.1.1 /usr/lib64/libssl.so.1.1
ln -s /usr/local/openssl-1.1.1w/lib/libcrypto.so.1.1 /usr/lib64/libcrypto.so.1.1

参考文章

• Gmssl编译问题: error while loading shared libraries: libssl.so.1.1: cannot open shared object file
• 如何平滑升级openssh,不影响root远程登录?