[19106] in bugtraq

home help back first fref pref prev next nref lref last post

Re: [CORE SDI ADVISORY] SSH1 session key recovery vulnerability

daemon@ATHENA.MIT.EDU (=?iso-8859-1?Q?Iv=E1n_Arce?=)
Fri Feb 9 17:47:18 2001

MIME-Version: 1.0
Content-Type: text/plain;  charset="iso-8859-1"
Content-Transfer-Encoding: 8bit
Message-ID:  <08ee01c092c5$f50daa60$2e58a8c0@ffornicario>
Date:         Fri, 9 Feb 2001 16:32:44 -0300
Reply-To: =?iso-8859-1?Q?Iv=E1n_Arce?= <core.lists.bugtraq@CORE-SDI.COM>
From: =?iso-8859-1?Q?Iv=E1n_Arce?= <core.lists.bugtraq@CORE-SDI.COM>
To: BUGTRAQ@SECURITYFOCUS.COM

Hello,

Yet another error in the advisory released last Wednesday.

----- Original Message -----
From: "Iván Arce" <core.lists.bugtraq@core-sdi.com>
Newsgroups: core.lists.bugtraq
To: <BUGTRAQ@SECURITYFOCUS.COM>
Sent: Wednesday, February 07, 2001 6:25 PM
Subject: [CORE SDI ADVISORY] SSH1 session key recovery vulnerability


>                                   CORE SDI
>                             http://www.core-sdi.com
>                 SSH protocol 1.5 session key recovery vulnerability
>
>

...
> -------------- cut here ----------------------------------------------
>
> --- rsaglue.c   1999/12/10 23:27:25     1.8
> +++ rsaglue.c   2001/02/03 09:42:05
> @@ -264,7 +268,15 @@
>    mpz_clear(&aux);
>
>    if (value[0] != 0 || value[1] != 2)
> -    fatal("Bad result from rsa_private_decrypt");
> +    {
> +      static time_t last_kill_time = 0;
> +      if (time(NULL) - last_kill_time > 60 && getppid() != 1)
> +       {
> +         last_kill_time = time(NULL);
> +         kill(SIGALRM, getppid());

... This is wrong wrong wrong and will produce unpredictable results
    on the server machine and does not fix the vulnerability either.
   The correct line is:

+         kill(getppid(),SIGALRM);

Thanks to Matt Power from the Bindview RAZOR Team for
pointing this out.

The advisory at our web page has been updateed to reflect this
change.


-ivan


---

"Understanding. A cerebral secretion that enables one having it to know
 a house from a horse by the roof on the house,
 Its nature and laws have been exhaustively expounded by Locke,
 who rode a house, and Kant, who lived in a horse." - Ambrose Bierce


==================[ CORE Seguridad de la Informacion S.A. ]=========
Iván Arce
Presidente
PGP Fingerprint: C7A8 ED85 8D7B 9ADC 6836  B25D 207B E78E 2AD1 F65A
email   : iarce@core-sdi.com
http://www.core-sdi.com
Florida 141 2do cuerpo Piso 7
C1005AAC Buenos Aires, Argentina.
Tel/Fax : +(54-11) 4331-5402
=====================================================================


--- For a personal reply use iarce@core-sdi.com

home help back first fref pref prev next nref lref last post