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SANS ISC InfoSec Forums

*** IMPORTANT UPDATE: ***



**OpenSSH 3.7.1p2 was released on September 23rd.**


It fixes additional security problems. No details yet.
****************************

A vulnerability has been discovered in OpenSSH which also affects the recent released versions 3.7p1 and 3.7.1p1.
We highly recommend upgrading to the version 3.7.1p2 which was released this morning. The new version 3.7.1p2 fixes additional related issues in the PAM module, not covered in 3.7.1p1.

This new bug may be remotely exploited according to the recently released announcement: "Under a non-standard configuration, with privsep disabled". This bug may not be exploitable on some platforms (e.g. OpenBSD) but could be exploitable on others (e.g. Linux).

Currently, there is no widely available exploit.

Workaround for this new bug (also affects 3.7p1 and 3.7.1p1)

(*) Upgrade to Portable OpenSSH 3.7.1p2 or disable PAM support ("UsePam no" in sshd_config).

(*) Allow only trusted hosts to access port 22

(*) Enable the 'Privilege Separation feature. It is not clear if this will prevent the current exploit. But it is likely to make any compromise harder
At the time of this writing, no major Linux distribution has released an official update.

OpenSSH is used in a number of devices sold by various vendors. Examples are Cisco and Juniper routers. We do not know at this point if these devices are vulnerable. Please contact your vendor for details.

Related links:

Portable OpenSSH Source:

ftp://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/

OpenSSH Web site:

http://www.openssh.org

OpenSSH Advisory:

http://www.openssh.com/txt/sshpam.adv
As always: Verify PGP signatures for any patches or files you download.

Relevant URLs for patches:

Linux:

Debian: http://www.debian.org/security/2003/dsa-382

Mandrake: http://www.mandrakesecure.net/en/advisories/advisory.php?name=MDKSA-2003:090

RedHat: http://www.redhat.com/apps/support/errata/

SUSE: http://www.suse.com/us/private/support/security/index.html (no ssh patch as of 19:30 EDT Sept. 16th)

Slackware: http://www.slackware.org


BSD:

FreeBSD: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-03:12.openssh.asc

NetBSD:
OpenBSD: http://www.openbsd.org/errata.html#sshbuffer
Please send additional relevant URLs to isc@sans.org

Not Vulnerable

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