Debian Long Term Support / LTS Security Information / 2016 / Security Information -- DLA-680-2 bash

Debian Security Advisory

DLA-680-2 bash -- LTS security update

Date Reported:

28 Oct 2016

Affected Packages:

bash

Vulnerable:

Yes

Security database references:

In Mitre's CVE dictionary: CVE-2016-7543.

More information:

This is a correction of DLA 680-1 that mentioned that bash 4.2+dfsg-0.1+deb7u3 was corrected. The corrected package version was 4.2+dfsg-0.1+deb7u4.

For completeness the text from DLA 680-1 available below with only corrected version information. No other changes.

An old attack vector has been corrected in bash (a sh-compatible command language interpreter).

• CVE-2016-7543

  Specially crafted SHELLOPTS+PS4 environment variables in combination with insecure setuid binaries.

  The setuid binary had to both use setuid() function call in combination with a system() or popen() function call. With this combination it is possible to gain root access.

  I addition bash have to be the default shell (/bin/sh have to point to bash) for the system to be vulnerable.

  The default shell in Debian is dash and there are no known setuid binaries in Debian with the, above described, insecure combination.

  There could however be local software with the, above described, insecure combination that could benefit from this correction.

For Debian 7 Wheezy, this problem have been fixed in version 4.2+dfsg-0.1+deb7u4.

We recommend that you upgrade your bash packages.

If there are local software that have the insecure combination and do a setuid() to some other user than root, then the update will not correct that problem. That problem have to be addressed in the insecure setuid binary.

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