Secunia

Some vulnerabilities and a security issue have been reported in DotNetNuke, which can be exploited by malicious users to gain escalated privileges or to compromise a vulnerable system, and by malicious people to bypass certain security restrictions.

1) The problem is that it is possible to upload static files, which can then be converted into dynamic scripts. This can be exploited to execute server-side application logic.

Successful exploitation requires access to the file manager and that the "HTM" or "HTML" file type has been added to the default file upload extensions.

2) An error in the file manager within the handling of allowed file types can be exploited to upload arbitrary files and gain escalated privileges.

Successful exploitation requires access to the file manager.

3) The problem is that under certain circumstances the "validationkey" is not generated properly. This can be exploited to access the portal as an arbitrary user, using the the unchanged default "validationkey".

The security issue and vulnerabilities are reported in versions prior to 4.8.2.

Solution
Update to version 4.8.2.
Further details available in Customer Area

Provided and/or discovered by
1) The vendor credits Timo Breumelhof.
2) The vendor credits Morteza Kermani.
3) Brian Holyfield

Changelog
Further details available in Customer Area

Original Advisory
http://www.dotnetnuke.com/News/SecurityBulletins/SecurityBulletinno11/tabid/1147/Default.aspx
http://www.dotnetnuke.com/News/SecurityBulletins/SecurityBulletinno12/tabid/1148/Default.aspx
http://www.dotnetnuke.com/News/SecurityBulletins/SecurityBulletinno13/tabid/1149/Default.aspx

Deep Links
Links available in Customer Area