CVE Vulnerabilities

CVE-2016-1255

Improper Link Resolution Before File Access ('Link Following')

Published: Dec 05, 2017 | Modified: Dec 21, 2017
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.2 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
Ubuntu

The pg_ctlcluster script in postgresql-common package in Debian wheezy before 134wheezy5, in Debian jessie before 165+deb8u2, in Debian unstable before 178, in Ubuntu 12.04 LTS before 129ubuntu1.2, in Ubuntu 14.04 LTS before 154ubuntu1.1, in Ubuntu 16.04 LTS before 173ubuntu0.1, in Ubuntu 17.04 before 179ubuntu0.1, and in Ubuntu 17.10 before 184ubuntu1.1 allows local users to gain root privileges via a symlink attack on a logfile in /var/log/postgresql.

Weakness

The software attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Name Vendor Start Version End Version
Postgresql-common Ubuntu esm-infra/xenial *
Postgresql-common Ubuntu precise *
Postgresql-common Ubuntu precise/esm *
Postgresql-common Ubuntu trusty *
Postgresql-common Ubuntu trusty/esm *
Postgresql-common Ubuntu upstream *
Postgresql-common Ubuntu xenial *
Postgresql-common Ubuntu yakkety *

Potential Mitigations

  • Follow the principle of least privilege when assigning access rights to entities in a software system.
  • Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

References