Padding oracle - Vulnerable Version of ASP.NET

Question

I would like to install the vulnerable version of ASP.NET for testing purposes. I've thought about it and I guess the best way would be to delete/disable some security updates to make that possible. Currently I'm running windows XP with all security updates installed.

On the following link http://weblogs.asp.net/scottgu/archive/2010/09/30/asp-net-security-fix-now-on-windows-update.aspx I've seen that the 3.5 ASP.NET security update was KB2416471, but I didn't found that update on my system, so I guess it must have the newer version of ASP.NET 3.5 installed which already has this fixed.

Any idea how would I get my hands on the system that is still vulnerable to the Padding Oracle on the ASP.NET Forms Authentication cookie to test it?

Answer 1

I would suggest running a virtual machine with external network disabled, and install a fresh OS from an old ISO image which predates the fix. Disabling external network prevents automatic installation of updates; it also blocks "Windows activation" so you will have only a few days or weeks to try it (but you can "stall" the clock between runs: since the VM has no external network, it has no way of cross-checking its knowledge of the internal clock).

If the VM technology is VirtualBox, use "Host-only networking" as described in the manual. This will allow your own desktop system to access the server in the VM.