I do not know if i am allowed to put link in this forum so i copy pasted a post from blizzhackers (hope its allowed , and hope i wont get banned for this ) :
Hopefully staff/devs will use this for twitter-style updates on Warden to keep our users informed on the safety of programs. (update title, too)
<Patch 0 - v.1.01.9558 - May 15th, 2012::RetailLaunch>
There was no clientside implementation of Warden with the retail launch version of Diablo III. That means there was no "WardenClient" to handle and interpret Warden requests sent from the server. The server sends modules (henceforth "warmods") which contain 'instructions' that tell Warden what to look for. These warmods can be changed serverside (sometimes referred to as "hotfixing"). That means Warden can receive new instructions at just about any time without you knowing. The warmods will use various tactics to seek out digital fingerprints of hacks. If you used a program that becomes detected, you are still okay as long as you don't use it actively after Warden has received specific instructions to look for evidence related to the hack. What you did before that is irrelevant.
<Patch 1.0.2 - v.1.0.2.9749 - May 29th, 2012::WardenImplemented>
As expected, Warden was implemented clientside with the first client patch. Now that the clientside responder is there, this means Warden is there. However, it can "watch" you hack all day long, but if it has no warmods with instruction sets, it will do nothing about it. At this time, there is no evidence of any warmods. Warden is running blind, and you should still be safe. That does not mean there will not be any warmods activated before the next patch, though! There is still risk to hacking now. They can write new instructions at any time and you will not be aware until it's too late if you don't use some kind of safety mechanism. To debunk a common mistake: Warden does NOT ban accounts. If you are caught cheating, it responds with a message to the server saying you are a bad player, and it flags your account to a blacklist for the next ban-wave.
D3Advanced users: Feel safer! D3Advanced will terminate Diablo 3 if it detects Warden loading any new warmods!
<June 4th (sometime around 4PM Cali time?? I was busy moving..>_>)>
I don't think this was actual Warden activity. Someone said rolle3k mentioned something about "Scan.dll". It was probably just delivered through Warden. If anyone has any further information, please post.