[30027] in bugtraq
Re: OpenSSH/PAM timing attack allows remote users identification
daemon@ATHENA.MIT.EDU (Marco Ivaldi)
Mon May 5 11:47:16 2003
Date: Mon, 5 May 2003 14:55:51 +0200 (CEST)
From: Marco Ivaldi <raptor@mediaservice.net>
To: Ethan Benson <erbenson@alaska.net>
In-Reply-To: <20030501091242.GE27626@plato.local.lan>
Message-ID: <Pine.LNX.4.30L2.0305051448480.20923-100000@dns.mediaservice.net>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
On Thu, 1 May 2003, Ethan Benson wrote:
> 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.
It is, also in the latest OpenSSH_3.6.1p2. I'm not sure if this behaviour
has serios security implications, however it can be "fixed" applying the
same workaround suggested for CAN-2003-0190: use the "nodelay" option for
pam_unix.so.
--
Marco Ivaldi
Chief Security Officer Data Security Division
@ Mediaservice.net Srl http://mediaservice.net/
