CVE-2016-2856

Published: 13 March 2016

pt_chown in the glibc package before 2.19-18+deb8u4 on Debian jessie; the elibc package before 2.15-0ubuntu10.14 on Ubuntu 12.04 LTS and before 2.19-0ubuntu6.8 on Ubuntu 14.04 LTS; and the glibc package before 2.21-0ubuntu4.2 on Ubuntu 15.10 and before 2.23-0ubuntu1 on Ubuntu 16.04 LTS and 16.10 lacks a namespace check associated with file-descriptor passing, which allows local users to capture keystrokes and spoof data, and possibly gain privileges, via pts read and write operations, related to debian/sysdeps/linux.mk. NOTE: this is not considered a vulnerability in the upstream GNU C Library because the upstream documentation has a clear security recommendation against the --enable-pt_chown option.

From the Ubuntu security team

Martin Carpenter discovered that pt_chown in the GNU C Library did not properly check permissions for tty files. A local attacker could use this to gain administrative privileges or expose sensitive information.

Priority

Medium

CVSS 3 base score: 8.4

Status

Package Release Status
eglibc
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr)
Released (2.19-0ubuntu6.8)
glibc
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(2.23-0ubuntu1)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

Patches:
Upstream: https://sourceware.org/git/?p=glibc.git;a=commit;h=77356912e83601fd0240d22fe4d960348b82b5c3