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Re: Security impact of removing timestamp check in rd_rep()

On Sun, 2005-05-15 at 17:04 -0400, Sam Hartman wrote:
> >>>>> "Luke" == Luke Howard <lukeh@PADL.COM> writes:
>     Luke> You actually want to check that they are different, to avoid
>     Luke> replay attacks.
> But you need to store all the timestamps you have seen in an allowable
> window.
> Really, I don't understand why you use a timestamp in a three-leg
> protocol.  It seems like you want to have a challenge in the second
> leg copied back in the third leg encrypted in a per-session key.
> However it sounds like DCE did not do this.

I think the sequence number is used for this.  It appears from the way
Microsoft implements their server, that they don't check the timestamps.

Now to figure out how to tell the krb5 layer that this is a DCE_STYLE
third leg...

Andrew Bartlett
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org
Student Network Administrator, Hawker College  http://hawkerc.net

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