Ubuntu Security Notice USN-2710-1
14th August, 2015
openssh vulnerabilities
A security issue affects these releases of Ubuntu and its
derivatives:
- Ubuntu 15.04
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS
Summary
Several security issues were fixed in OpenSSH.
Software description
- openssh
– secure shell (SSH) for secure access to remote machines
Details
Moritz Jodeit discovered that OpenSSH incorrectly handled usernames when
using PAM authentication. If an additional vulnerability were discovered in
the OpenSSH unprivileged child process, this issue could allow a remote
attacker to perform user impersonation. (CVE number pending)
Moritz Jodeit discovered that OpenSSH incorrectly handled context memory
when using PAM authentication. If an additional vulnerability were
discovered in the OpenSSH unprivileged child process, this issue could
allow a remote attacker to bypass authentication or possibly execute
arbitrary code. (CVE number pending)
Jann Horn discovered that OpenSSH incorrectly handled time windows for
X connections. A remote attacker could use this issue to bypass certain
access restrictions. (CVE-2015-5352)
It was discovered that OpenSSH incorrectly handled keyboard-interactive
authentication. In a non-default configuration, a remote attacker could
possibly use this issue to perform a brute-force password attack.
(CVE-2015-5600)
Update instructions
The problem can be corrected by updating your system to the following
package version:
- Ubuntu 15.04:
-
openssh-server
1:6.7p1-5ubuntu1.2
- Ubuntu 14.04 LTS:
-
openssh-server
1:6.6p1-2ubuntu2.2
- Ubuntu 12.04 LTS:
-
openssh-server
1:5.9p1-5ubuntu1.6
To update your system, please follow these instructions:
https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.