Debian DLA-1500-2 : openssh regression update

High Nessus Plugin ID 117432

Synopsis

The remote Debian host is missing a security update.

Description

The security update of OpenSSH announced as DLA 1500-1 introduced a bug in openssh-client: when X11 forwarding is enabled (via system-wide configuration in ssh_config or via -X command line switch), but no DISPLAY is set, the client produces a 'DISPLAY '(null)' invalid;
disabling X11 forwarding' warning. These bug was introduced by the patch set to fix the CVE-2016-1908 issue. For reference, the following is the relevant section of the original announcement :

CVE-2016-1908

OpenSSH mishandled untrusted X11 forwarding when the X server disables the SECURITY extension. Untrusted connections could obtain trusted X11 forwarding privileges. Reported by Thomas Hoger.

For Debian 8 'Jessie', this problem has been fixed in version 1:6.7p1-5+deb8u7.

We recommend that you upgrade your openssh packages.

NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Solution

Upgrade the affected packages.

See Also

https://lists.debian.org/debian-lts-announce/2018/09/msg00014.html

https://packages.debian.org/source/jessie/openssh

Plugin Details

Severity: High

ID: 117432

File Name: debian_DLA-1500.nasl

Version: 1.2

Type: local

Agent: unix

Published: 2018/09/12

Modified: 2018/09/13

Dependencies: 12634

Risk Information

Risk Factor: High

Temporal Vector: CVSS2#E:ND/RL:OF/RC:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:openssh-client, p-cpe:/a:debian:debian_linux:openssh-client-udeb, p-cpe:/a:debian:debian_linux:openssh-server, p-cpe:/a:debian:debian_linux:openssh-server-udeb, p-cpe:/a:debian:debian_linux:openssh-sftp-server, p-cpe:/a:debian:debian_linux:ssh, p-cpe:/a:debian:debian_linux:ssh-askpass-gnome, p-cpe:/a:debian:debian_linux:ssh-krb5, cpe:/o:debian:debian_linux:8.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Patch Publication Date: 2018/09/12