Debian Security Advisory
DLA-1500-2 openssh -- LTS security update
- Date Reported:
- 12 Sep 2018
- Affected Packages:
- Security database references:
- In the Debian bugtracking system: Bug 908652.
- More information:
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:
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.
Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS