USN-3294-1: Bash vulnerabilities

Publication date

17 May 2017

Overview

Several security issues were fixed in Bash.


Packages

  • 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...

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

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

Learn more about how to get the fixes.

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

Ubuntu Release Package Version
17.04 zesty bash –  4.4-2ubuntu1.1
16.10 yakkety bash –  4.3-15ubuntu1.1
16.04 xenial bash –  4.3-14ubuntu1.2
14.04 trusty bash –  4.3-7ubuntu1.7

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