Full Disclosure mailing list archives

Re: OpenSSH - System Account Enumeration if S/Key is used


From: "Brian Eaton" <eaton.lists () gmail com>
Date: Tue, 24 Apr 2007 10:06:58 -0400

On 4/24/07, Stanislaw Klekot <dozzie () dynamit im pwr wroc pl> wrote:
Look closer to challenge message. There's salt and key number included.
Consider now three logins: first isn't valid account on the target
system, second is valid but without OTP set, and third with OTP set.
First two are indistinguishable for attacker as in these cases system
presents random challenge, but for third account system will present the
same challenge over and over again.

How about that?

Perhaps rather than presenting a random challenge, the challenge could
be based on a hash of the account name used and a per-system salt?

Regards,
Brian

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