USN-3538-1: OpenSSH vulnerabilities

Ubuntu Security Notice USN-3538-1

22nd January, 2018

openssh vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 17.10
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS

Summary

Several security issues were fixed in OpenSSH.

Software description

  • openssh - secure shell (SSH) for secure access to remote machines

Details

Jann Horn discovered that OpenSSH incorrectly loaded PKCS#11 modules from
untrusted directories. A remote attacker could possibly use this issue to
execute arbitrary PKCS#11 modules. This issue only affected Ubuntu 14.04
LTS and Ubuntu 16.04 LTS. (CVE-2016-10009)

Jann Horn discovered that OpenSSH incorrectly handled permissions on
Unix-domain sockets when privilege separation is disabled. A local attacker
could possibly use this issue to gain privileges. This issue only affected
Ubuntu 16.04 LTS. (CVE-2016-10010)

Jann Horn discovered that OpenSSH incorrectly handled certain buffer memory
operations. A local attacker could possibly use this issue to obtain
sensitive information. This issue only affected Ubuntu 14.04 LTS and Ubuntu
16.04 LTS. (CVE-2016-10011)

Guido Vranken discovered that OpenSSH incorrectly handled certain shared
memory manager operations. A local attacker could possibly use issue to
gain privileges. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04
LTS. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS.
(CVE-2016-10012)

Michal Zalewski discovered that OpenSSH incorrectly prevented write
operations in readonly mode. A remote attacker could possibly use this
issue to create zero-length files, leading to a denial of service.
(CVE-2017-15906)

Update instructions

The problem can be corrected by updating your system to the following package version:

Ubuntu 17.10:
openssh-server 1:7.5p1-10ubuntu0.1
Ubuntu 16.04 LTS:
openssh-server 1:7.2p2-4ubuntu2.4
Ubuntu 14.04 LTS:
openssh-server 1:6.6p1-2ubuntu2.10

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.

References

CVE-2016-10009, CVE-2016-10010, CVE-2016-10011, CVE-2016-10012, CVE-2017-15906