WebApp Sec mailing list archives
RE: Https sniffer
From: "Phalak, Kashmira Vijay" <kphalak () verisign com>
Date: Thu, 21 Jul 2005 11:37:50 -0700
Rogan, Thanks for the explanation..that was really helpful! Now that I'm pretty much clear on this, I will have to pass up the idea of using a HTTPS sniffer as it would require the server's private key and look at some MITM tools such as Dsniff, EtterCap etc. as suggested by you and other members. Imre gave some really good suggestions too and I read up on stunnel and I think it would be worth a try for my purpose. Thank you all for your help... Regards, Kashmira. -----Original Message----- From: Rogan Dawes [mailto:discard () dawes za net] Sent: Wednesday, July 20, 2005 11:54 PM To: Phalak, Kashmira Vijay Cc: vuln-dev () securityfocus com; webappsec () securityfocus com Subject: Re: Https sniffer Phalak, Kashmira Vijay wrote:
Hi All, Thanks for your suggestions! But most of these products suggested need
the private key to be supplied for decrypting the SSL traffic. The HTTP Analyzer which I initially tried, does not need the private key to be supplied and does a good job of decrytping SSL traffic. Can anyone explain to me how this works? But the HTTP analyzer only sniffs
the traffic in the current user session. This behavior is different from that of ethereal when I set it in promiscuous mode. Here, I can see traffic from other machines on the same ether segment. I may be wrong here, but I don't see this in either ClearWatch,ssldump or
ngrep.
Thanks, Kashmira.
Hi Kashmira, The way that the tool that you have been using works is by accessing the WinInet debugging interfaces, and getting the information as it is decrypted by the MS SSL libraries. This is possible without the server's private key, because it is accessing the client's negotiated symmetric keys, I guess. Of course, if you were to use any other non-WinInet SSL libraries (e.g. OpenSSL, FireFox, etc) HTTP Analyser would not be able to do anything at all. So, the significant difference between HTTP Analyser, and the other tools that have been suggested, is that HTTP Analyser is not actually sniffing the network at all, whereas the other recommendations do (and hence CAN support a promiscuous mode). If you want to perform promiscuous network sniffing, AND decrypt SSL communications that you collect in this way, you WILL need the servers' private keys. There is no other way (short of "breaking" SSL). The alternative, if you can convince the other parties on the network to use you as a proxy, is to set up something like DSniff's SSL MITM, or WebScarab, and intercept the connections. This would enable you to get the clear text comms for a number of clients on the network, at the cost of a certificate error pop-up in each client. Regards, Rogan
Current thread:
- Https sniffer Phalak, Kashmira Vijay (Jul 19)
- Re: Https sniffer Hugo Fortier (Jul 19)
- RE: Https sniffer Lyal Collins (Jul 20)
- Re: Https sniffer Garth Somerville (Jul 20)
- <Possible follow-ups>
- RE: Https sniffer Asaf Wexler (Jul 20)
- RE: Https sniffer Phalak, Kashmira Vijay (Jul 20)
- RE: Https sniffer Garth Somerville (Jul 21)
- Re: Https sniffer Rogan Dawes (Jul 21)
- Re: Https sniffer Achim Hoffmann (Jul 21)
- RE: Https sniffer Erick Lee (Jul 21)
- RE: Https sniffer Phalak, Kashmira Vijay (Jul 21)
- Re: Https sniffer Hugo Fortier (Jul 19)