WebApp Sec mailing list archives
RE: Client script access to server cert info
From: "Dawes, Rogan (ZA - Johannesburg)" <rdawes () deloitte co za>
Date: Wed, 16 Apr 2003 17:48:21 +0200
I did a quick search for Tony's search term, and it looks like he was referring to a server side solution. What Phil was looking for was a client side solution, so that the client could check if the *server's* cert was invalid. I would be looking for some function in JavaScript, or possibly a Java LiveConnect or ActiveX component to be able to do this. I think Jon has misunderstood what Phil was asking for, although he does seem to be looking for what Tony was referring to! :-) For Jon's purposes, I would suggest something like: As a key, encrypt some static data using the client's server certificate (this will tie the key to the lifetime of the certificate, and renewing the ssl server cert will require getting a new application key as well.) Configure the application to be able to use the SSL private key to decrypt the license key, and verify that the static text is intact. If they cannot decrypt the static key, then they don't have the right server cert, and so they shouldn't be using the application. Unfortunately, it all falls flat because you are using Perl, and it would be trivial to bypass the checks, simply because perl is source code, not binary. Even the attempts at compiling perl only delay an attacker by a few minutes, since all perl obfuscation modules can be trivially reversed (see a fairly recent discussion here or on the secure programming list for details, I forget which) Nice try, thanks for p(l)aying. Rogan -----Original Message----- From: Jon Pastore [mailto:jpastore () idetech net] Sent: 16 April 2003 01:18 PM To: Maupin, Tony; 'Brass, Phil (ISS Atlanta)'; webappsec () securityfocus com Subject: Re: Client script access to server cert info can you recommend one for perl? CPAN wasn't playing nice when I did a search eariler...I have an intranet application I sell based on perl that it would be nice if we could make sure it only runs on the computer it was told to. and being able to analyze the cert would be nice... -Jon ----- Original Message ----- From: "Maupin, Tony" <Tony.Maupin () integris-health com> To: "'Brass, Phil (ISS Atlanta)'" <PBrass () iss net>; <webappsec () securityfocus com> Sent: Monday, April 14, 2003 9:55 AM Subject: RE: Client script access to server cert info
What you're looking for is called a "certificate parsing module". Do a search on that term and/or add open source to the search depending on what you're looking for. It will do everything you are asking and more. Tony Maupin -----Original Message----- From: Brass, Phil (ISS Atlanta) [mailto:PBrass () iss net] Sent: Sunday, April 13, 2003 11:21 PM To: webappsec () securityfocus com Subject: RE: Client script access to server cert info To clarify, what I'm looking for is a way for script on a page to access the server certificate information used during the SSL connection over which the page was provided. I.e. if Alice requests a page from bob.com, but the bob.com server returns a certificate that actually says mallory.com, and Alice presses "OK" when prompted about the discrepancy, it would be nice if there was a way to detect this using script that ran in the browser. I'm trying to find out if anybody knows of any browser/DOM/DHTML objects that contain a description (signing chain, CN, fingerprint, whatever) of the actual server certificate information presented during the SSL handshake. Phil-----Original Message----- From: Brass, Phil (ISS Atlanta) Sent: Sunday, April 13, 2003 11:51 PM To: webappsec () securityfocus com Subject: Client script access to server cert info Does anybody know if there is a way to access the server certificate information in client-side script in a web browser? Thanks! Phil
Current thread:
- Client script access to server cert info Brass, Phil (ISS Atlanta) (Apr 13)
- <Possible follow-ups>
- RE: Client script access to server cert info Brass, Phil (ISS Atlanta) (Apr 13)
- RE: Client script access to server cert info Dawes, Rogan (ZA - Johannesburg) (Apr 14)
- RE: Client script access to server cert info Maupin, Tony (Apr 14)
- Re: Client script access to server cert info Jon Pastore (Apr 16)
- RE: Client script access to server cert info Dawes, Rogan (ZA - Johannesburg) (Apr 16)
- Re: Client script access to server cert info n30 (Apr 16)
- RE: Client script access to server cert info Jimi Thompson (Apr 16)