Question

How can I dynamically clear the Internet Explorer SSL Cache?

Asked by: YAST_AngelRipper

Hi Everybody.

I got the following Problem:

We have  developed a complete ASP.NET application for the management of employees' trainings.
For the next version our customers want  the possibility that the employees can confirm their presence in a training
by using smartcard and pin.

So far this would be no problem but the scenario has to be the following:

1. The client is once logged in with any user account and also the training web tool is opened and logged
with any account. No log off spould happen at all!

2. The list with the participants of a training is opened ant the application waits for authentications.
One employee authenticates himself by inserting his card and typing his pin.
The certificate is being read from the smartcard and its validity is checked.
This part of the process is being done by a third-party interface which is not possible to be changed. (I'd love to but I can'tt)
After that our application writes the successful authentication to the database.

Directly after the first user has validated himself we need to be able to check other user cards and their pin.

And now comes the problem:
The Internet Explorer 6 Sp1 caches the just recieved certificate in its SSL cache and does not initialize the
card reader interface again, it just "remembers" the last used certificate and uses this again.
That way, our application will do nothing (correctly!), because that user has just authenticated his presence.

To avoid this problem we can
a) close the browser window and even that may not be enough, MS says "Restarting Windows" is the way to clear that chache OR
b) Go to Extras -> Internet Options -> Content -> Clear SSL State

I now need to know either
a) how to prevent the caching of the certificate at all.
or
b) how I can reset the client (!) ssl cache in internet explorer with help of some activeX control or something like that

I found hints regarding winHTTP or winINET classes and schannel.dlll and information that it could be done using
anything of those, but no exact information.

Any help would be really greatly appreciated,
because I've been trying to get this working for the last two weeks and still no light at the end of the tunnel...

Greetings,

Angel

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Asked On
2004-07-07 at 01:31:53ID21050212
Tags

ssl

,

clear

Topic

Web Browsers

Participating Experts
1
Points
500
Comments
15

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Answers

 

by: VincentPugliaPosted on 2004-07-08 at 08:00:25ID: 11502745

Hi,

did some googling ("ssl cache" prevent) ("ssl cache" winINET) and came up with:

http://support.microsoft.com/default.aspx?scid=kb;en-us;330338

and a thread in a userforum that said:
1) prior to IE6, the cache cannot be cleared
2) pointed to this book:
http://www.microsoft.com/mspress/books/5612.asp

Vinny

 

by: YAST_AngelRipperPosted on 2004-07-08 at 22:26:38ID: 11509096

Thanks a lot for the research at first, Vinny.

We got IE 6SP1 and XP and I also changed some RegistryKeys (the one mentioned above too)
already but with no effect so far.

The funny thing is: The problem exists since IE5, and since IE6 there's the reset SSL status
button, but that does not help...

 We are currently trying to put up a solutiion with a hidden frame
in which the certificate request is sent to the interface and after transaction
we are trying to clear the content in the hidden frame so far that we maybe
can get a new request to run...

My favourite way would still be to fond ANY way to clear the cache by code,
even if it is in a standalone client application and not by a browser script...

 

by: VincentPugliaPosted on 2004-07-09 at 04:33:34ID: 11510509

Hi,

Perhaps the Microsoft SOAP Toolkit 2.0  

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnsoap/html/soapsecurity.asp

The following code & paragraph (from above link) makes me think that the toolkit may have hooks you can use.

Set Calc = CreateObject("MSSOAP.SoapClient")
Calc.mssoapinit https://your-server/MSSoapSamples/Calc/Service/Rpc/
     AspVbsVb/Calc.wsdl
Answer = Calc.add(14,28)
WScript.Echo "14+28=" & Answer

You have just made a connection through SSL. Note that if you change the URLs back to HTTP, you will be making a regular non-secure HTTP connection. To make your server require an SSL connection for your Web service, you need to set SSL required on the virtual directory your service is located in.

Vinny




 

by: YAST_AngelRipperPosted on 2004-08-04 at 03:51:15ID: 11713940

I am really sorry, I made a mistake and somehow failed to submit my last comment...

The problem with VincentPuglia's solution is:

I do not really need to establish a  SSL connection.

I really just need to be able to pass an authentication via cardreader and then force IE6sp1 to forget the SSL certificate
that was cached by this authentication for the next user with his card.

Even if I do this by SSL connections the problem would by that IE caches the certificate and would not ask me for
authorization again afterwards

So far, problem still not solved.
We have come to the conclusion so far that it possibly cannotz be done (reseting the ssl cache dynamically) and try
to find workarounds.

But I personally am still very interested if this could be done,
so check your brains to get the points and find an answer to the basic question:

Can I empty the IE's SSL cache via code?


 

by: YAST_AngelRipperPosted on 2004-08-04 at 03:53:47ID: 11713968

I hust would like to add a thing:

I of course realize that maybe there was already a solution and I am just to stupid to see,
so if that is so:
Please give me an example of code or atr least a description of the necessary elements and steps.

Thanks guys!

 

by: VincentPugliaPosted on 2004-08-04 at 05:40:10ID: 11714695

Hi Angel,

  I agree the q wasn't answered.  Mostly because this is really beyond my experience...:(

However, you might find the following helpful, it comes from:

http://www.microsoft.com/technet/prodtechnol/windows2000serv/technologies/iis/maintain/optimize/c12iis.mspx

Controlling Secure Sockets Layer Through the Registry
Settings that control Secure Sockets Layer (SSL) are stored in the Registry under

HKEY_LOCAL_MACHINE
 \SYSTEM \CurrentControlSet \Control \SecurityProviders \SCHANNEL

After you've started the Registry Editor and accessed this location, the key values you might want to work with are

• EventLogging Determines whether SSL connections are logged for Web sites configured on the server. By default, this value is enabled (set to 1). To disable this feature, set the value to 0.
 
• ServerCacheTime Determines the amount of time (in milliseconds) that an SSL session lasts. Establishing an SSL session is a time- and resource-intensive process. If you expect SSL sessions to last, on average, longer than the default value, you might want to modify this value. By default, an SSL session lasts 5 minutes (300,000 milliseconds). When the session expires, a new SSL session must be established.
 
Also on the page is a reference to 'The Scripting Bible' (or somesuch), a book you might find useful.

 

by: VincentPugliaPosted on 2004-09-14 at 11:08:28ID: 12057720

Hi Venabili,

  Don't know that I should actually get the points since I really didn't solve his problem (see my previous post).  True, I may have helped some, but....no ring on the merry-go-round.  :)

Vinny

 

by: YAST_AngelRipperPosted on 2004-09-14 at 23:10:32ID: 12061693

Well... he really didn't find "the solution" , in the meantime I'm nearly convinced
that it cannot be done though, and Vincent gave a reaql good try to find something, so I guess he
has earned something at least

 

by: VincentPugliaPosted on 2004-09-15 at 04:51:42ID: 12063443

Hi Angel :)

  Thanks for the comment :D

 

by: YAST_AngelRipperPosted on 2004-09-16 at 00:03:21ID: 12072440

Hi Vincent.

Do you know how this works here?
If I accepted your comments as a solution and  gave you the points
would the whole thread then be saved as a solution?

By the way, did I mention the workaround yet that we are using now:

I do not clear the SSL cache dynamically at all,
I open a PopUp Window which is not part of the entire application
(It is an ASP page, the rest is ASP.NET with c#)
The request is submitted in an HTML page which is enbedded in an  IFRAME.
After recieving the results of the 3rd party interface which does the PIN request
and the login of the smartcard I shut down the pop up and VOILA:
The certificate is not cached and the next time I call the login the PIN is requested again!!

 

by: VincentPugliaPosted on 2004-09-16 at 04:01:23ID: 12073530

Beautiful !  :D  And I should have thought of it myself, especially since I recommend iframes as solutions for other problems where people don't want to refresh the main windows.

Re the saving: I'm really not sure, but I presume everything is saved.

Vinny

 

by: YAST_AngelRipperPosted on 2004-09-16 at 05:17:53ID: 12073908

well, then i guess I'll just accept your comments and you earn the points!

Thanks a lot Vinny for your efforts and cu sometime again maybe!

 

by: VincentPugliaPosted on 2004-09-16 at 05:42:42ID: 12074060

You're welcome, and you never know...cya later, gater
:D

20120131-EE-VQP-002

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