On Mon, Nov 10, 2003 at 11:23:16AM +1300, Jason Haar wrote:
> On Fri, 2003-11-07 at 21:45, Lutz Jaenicke wrote:
> > When you are using s_client, you will most likely negotiate an EDH cipher
> > that cannot be decrypted with ssldump. Use
> > openssl -s_client -ciphers RC4-MD5 ...
> > to generate "decryptable" sessions...
>
> Ah - thank you - that makes total sense (and also allows me to see it
> working :-).
>
> It's just that I see people who keep mentioning ssldump as some magic
> tool that will allow you to decrypt all that traffic going to your
> SSL-protected application. Whereas the reality is that will only work if
> a static RSA cipher such as RC4-MD5 is negotiated during SSL setup.
>
> So you really have to force your SSL server to exclusively support such
> ciphers to be able to reliably decrypt SSL traffic, and yet they are not
> the most secure of options available.
>
> So in reality, even having access to the server certificate(s) doesn't
> allow you to decrypt SSL traffic except when you go out of your way to
> force the app to use a less secure crypto option.
That's why EDH is strongly recommended for SSL/TLS sessions. For other
protocols, namely SSH, ephemeral key exchange is a basic component, static
key handling is not even possible.
So the question is what you intend to achieve: if you intend to be able
to decrypt the sessions of your own server you will have to record the
session keys... e.g. by permanently saving the session data.
On the other hand, you may simply record the plaintext data sent by your
server anyway...
Best regards,
Lutz
--
Lutz Jaenicke [EMAIL PROTECTED]
http://www.aet.TU-Cottbus.DE/personen/jaenicke/
BTU Cottbus, Allgemeine Elektrotechnik
Universitaetsplatz 3-4, D-03044 Cottbus
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