[29973] in bugtraq
Re: OpenSSH/PAM timing attack allows remote users identification
daemon@ATHENA.MIT.EDU (Ethan Benson)
Thu May 1 13:47:29 2003
Date: Thu, 1 May 2003 01:12:42 -0800
From: Ethan Benson <erbenson@alaska.net>
To: Marco Ivaldi <raptor@mediaservice.net>
Message-ID: <20030501091242.GE27626@plato.local.lan>
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On Wed, Apr 30, 2003 at 04:34:27PM +0200, Marco Ivaldi wrote:
> root@voodoo:~# ssh [valid_user]@lab.mediaservice.net
> [valid_user]@lab.mediaservice.net's password: <- arbitrary (non-null) str=
ing
> [2 secs delay]
> Permission denied, please try again.
>=20
> root@voodoo:~# ssh [no_such_user]@lab.mediaservice.net
> [no_such_user]@lab.mediaservice.net's password: <- arbitrary (non-null) s=
tring
> [no delay]
> Permission denied, please try again.
ive noticed something similar in its handling of PermitRootLogin, if
this option is set to `no' you get the following behavior:
$ ssh root@host
root@host's password: <- arbitrary (non-null) string
[2 secs delay]
Permission denied, please try again.a
$ ssh root@host
root@host's password: <- correct root password
[no delay]
Permission denied, please try again.
i haven't checked the current version to see if this is still true.=20
i think you also will get no delay if DenyUsers or so is in use for
accounts your testing.
--=20
Ethan Benson
http://www.alaska.net/~erbenson/
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