[image: Vulnerable Umbraco]
<http://blog.securelayer7.net/wp-content/uploads/2016/02/download.png>

Recently I got an assignment where I had to work on the Umbraco application
- a free Open Source Content Management System built on the ASP.NET
platform and is used by more than 2,25,000 websites. While performing the
security testing of this application, I discovered serious vulnerabilities
within this application, allowing to perform SSRF attack, CSRF Bypass
attack, and persistent XSS. The CVE number yet to be assigned to these
vulnerabilities. It would be strongly recommended to update the CMS to
latest version.

*SSRF Vulnerability*

Let me get start with Server side request forgery (ssrf) attack found
within the feedproxy.aspx. Those who new to SSRF, please follow this link.
<https://cwe.mitre.org/data/definitions/918.html>

I started off playing with the feedproxy.aspx, it is intersting page in
Umbraco . the feedproxy.aspx is used to access the external resources using
the URL GET parameter.

http://local/Umbraco/feedproxy.aspx?url=http://bobsite/index

once you change the URL to the
http://local/Umbraco/feedproxy.aspx?url=http://127.0.0.1:80/index, you able
to access the localhost application of the server.

Using this payload change the port number to perform port scanning of the
server. It will be helpful to find the more details of the server.
For example:

http://local/Umbraco/feedproxy.aspx?url=http://127.0.0.1:25/index
http://local/Umbraco/feedproxy.aspx?url=http://127.0.0.1:8080/index

If the port number is closed, you will find the error message on the
feedproxy.aspx page. Umbraco assigned bug ID U4-7457
<http://issues.umbraco.org/issue/U4-7457> and fixed the issue.

*CSRF Bypass Vulnerability*

The Umbraco assigned bug ID U4-7459
<http://issues.umbraco.org/issue/U4-7459>, It was discovered that Umbraco
enabled sensitive actions, such as editing a user account information was
vulnerable to CSRF vulnerability.
The vulnerable code in templates.asmx.cs on the line number 75, it is
executing save operation without verifying the actual CSRF token.
In the file SetAngularAntiForgeryTokensAttributes.cs, on line number 25,
function allowing empty CSRF value, the CSRF vulnerability is triggering.

Find the more details on this fix on the below given link:

https://github.com/umbraco/Umbraco-CMS/commit/18c3345e47663a358a042652e697b988d6a380eb

*Persistent XSS Vulnerability*

It is found that Umbraco is also vulnerable to Persistent XSS in content
type editor. Umbraco has been assigned bug ID U4-7461.. This vulnerability
existed in the name field of the media page, the developer data edit page,
and the form page.[image: XSS Vulnerability in Umbraco]
<http://blog.securelayer7.net/wp-content/uploads/2016/02/3-1.png>

[image: XSS Vulneraiblity in Umbraco]
<http://blog.securelayer7.net/wp-content/uploads/2016/02/1.png>

[image: XSS Vulnerability Umbraco]
<http://blog.securelayer7.net/wp-content/uploads/2016/02/2.png>

To mitigate these vulnerabilities, it is recommended to update Umbraco to
the version V7.4.0.