查看Nginx默认是显示版本号

curl -I 127.0.0.1:80/index.html 

HTTP/1.1 200 OK
Server: nginx/1.17.3
Date: Tue, 11 Feb 2020 03:26:52 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 3888
Last-Modified: Fri, 20 Sep 2019 03:17:19 GMT
Connection: keep-alive
Keep-Alive: timeout=15
ETag: "5d8444bf-f30"
Content-Encoding: gzip

这样就给别人看到服务器nginx版本是1.17.3，有了已知版本，将缩小检测范围，攻击者就会根据对应的nginx版本，要对版本存在漏洞，进行针对性攻击。

进入nginx配置文件的目录，在http { }段里加上server_tokens off; 如：

http {
    server_tokens off;
    include       mime.types;
    default_type  application/octet-stream;
    ... 省略其他 ... 
}

如fastcgi.conf或fcgi.conf（这个配置文件名也可以自定义的，根据具体文件名修改）：

找到：
fastcgi_param SERVER_SOFTWARE nginx/$nginx_version;
改为：
fastcgi_param SERVER_SOFTWARE nginx;

#测试、重载nginx配置
nginx -t
# 得到如下结果：
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful
 
## 重载配置
nginx -s reload

curl -I 127.0.0.1:80/index.html 

HTTP/1.1 200 OK
Server: nginx
Date: Tue, 11 Feb 2020 03:26:52 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 3888
Last-Modified: Fri, 20 Sep 2019 03:17:19 GMT
Connection: keep-alive
Keep-Alive: timeout=15
ETag: "5d8444bf-f30"
Content-Encoding: gzip