Full Disclosure mailing list archives
Re: OpenSSH - System Account Enumeration if S/Key is used
From: Stanislaw Klekot <dozzie () dynamit im pwr wroc pl>
Date: Tue, 24 Apr 2007 11:10:27 +0200
On Sat, Apr 21, 2007 at 02:27:17AM +0200, rembrandt wrote:
As you can see clearly OpenSSH discloses the existence of system accounts. A possible solution for this problem would be to print a fake S/Key-Request even for non existing users as well as it`s done with the Passwordauthentication.
This issue is known not only for S/Key, but for OPIE (PAM version) as well, although it's a bit different for the latter. 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? -- Stanislaw Klekot _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- OpenSSH - System Account Enumeration if S/Key is used rembrandt (Apr 20)
- Re: OpenSSH - System Account Enumeration if S/Key is used Stanislaw Klekot (Apr 24)
- Re: OpenSSH - System Account Enumeration if S/Key is used Brian Eaton (Apr 24)
- Re: OpenSSH - System Account Enumeration if S/Key is used rembrandt (Apr 24)
- Re: OpenSSH - System Account Enumeration if S/Key is used Nico Golde (Apr 25)
- Re: OpenSSH - System Account Enumeration if S/Key is used Knud Erik Højgaard (Apr 25)
- Re: OpenSSH - System Account Enumeration if S/Key is used Kradorex Xeron (Apr 25)
- Re: OpenSSH - System Account Enumeration if S/Key is used Knud Erik Højgaard (Apr 25)
- Re: OpenSSH - System Account Enumeration if S/Key is used Stanislaw Klekot (Apr 24)