Synopsis: Low: sudo security and bug fix update
Advisory ID: SLSA-2013:1353-1
Issue Date: 2013-09-30
CVE Numbers: CVE-2013-1775
A flaw was found in the way sudo handled time stamp files. An attacker
able to run code as a local user and with the ability to control the
system clock could possibly gain additional privileges by running commands
that the victim user was allowed to run via sudo, without knowing the
victim’s password. (CVE-2013-1775)
It was found that sudo did not properly validate the controlling terminal
device when the tty_tickets option was enabled in the /etc/sudoers file.
An attacker able to run code as a local user could possibly gain
additional privileges by running commands that the victim user was allowed
to run via sudo, without knowing the victim’s password. (CVE-2013-1776,
This update also fixes the following bugs:
* Due to a bug in the cycle detection algorithm of the visudo utility,
visudo incorrectly evaluated certain alias definitions in the /etc/sudoers
file as cycles. Consequently, a warning message about undefined aliases
appeared. This bug has been fixed, /etc/sudoers is now parsed correctly by
visudo and the warning message no longer appears.
* Previously, the ‘sudo -l’ command did not parse the /etc/sudoers file
correctly if it contained an Active Directory (AD) group. The file was
parsed only up to the first AD group information and then the parsing
failed with the following message:
sudo: unable to cache group ADDOM\admingroup, already exists
With this update, the underlying code has been modified and ‘sudo -l’ now
parses /etc/sudoers containing AD groups correctly.
* Previously, the sudo utility did not escape the backslash characters
contained in user names properly. Consequently, if a system used sudo
integrated with LDAP or Active Directory (AD) as the primary
authentication mechanism, users were not able to authenticate on that
system. With this update, sudo has been modified to process LDAP and AD
names correctly and the authentication process now works as expected.
* Prior to this update, the ‘visudo -s (strict)’ command incorrectly
parsed certain alias definitions. Consequently, an error message was
issued. The bug has been fixed, and parsing errors no longer occur when
using ‘visudo – -s’.
– Scientific Linux Development Team