7.2 - USN-3294-1

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

- Ubuntu 17.04 - Ubuntu 16.10 - Ubuntu 16.04 LTS - Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in Bash.

Software Description: - bash: GNU Bourne Again SHell

Details:

Bernd Dietzel discovered that Bash incorrectly expanded the hostname when displaying the prompt. If a remote attacker were able to modify a hostname, this flaw could be exploited to execute arbitrary code. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-0634)

It was discovered that Bash incorrectly handled the SHELLOPTS and PS4 environment variables. A local attacker could use this issue to execute arbitrary code with root privileges. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-7543)

It was discovered that Bash incorrectly handled the popd command. A remote attacker could possibly use this issue to bypass restricted shells. (CVE-2016-9401)

It was discovered that Bash incorrectly handled path autocompletion. A local attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 17.04. (CVE-2017-5932)

Update instructions:

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

Ubuntu 17.04:
bash 4.4-2ubuntu1.1

Ubuntu 16.10:
bash 4.3-15ubuntu1.1

Ubuntu 16.04 LTS:
bash 4.3-14ubuntu1.2

Ubuntu 14.04 LTS:
bash 4.3-7ubuntu1.7

In general, a standard system update will make all the necessary changes.

References:
http://www.ubuntu.com/usn/usn-3294-1
CVE-2016-0634, CVE-2016-7543, CVE-2016-9401, CVE-2017-5932

Package Information:
https://launchpad.net/ubuntu/+source/bash/4.4-2ubuntu1.1
https://launchpad.net/ubuntu/+source/bash/4.3-15ubuntu1.1
https://launchpad.net/ubuntu/+source/bash/4.3-14ubuntu1.2
https://launchpad.net/ubuntu/+source/bash/4.3-7ubuntu1.7