Vigil@nce: FreeBSD, directory access via jail
May 2010 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/
SYNTHESIS OF THE VULNERABILITY
In some FreeBSD jail usage cases, an attacker inside the jail can
access to an external directory.
– Severity: 1/4
– Creation date: 27/05/2010
DESCRIPTION OF THE VULNERABILITY
The /usr/sbin/jail command is used to create a jail, where a
process cannot access to system resources.
However, the jail command does not change the current directory,
except if "-l -U root" parameters are used. An attacker inside the
jail can therefore access to the file descriptor of the current
directory where the command was launched.
This command can be called from the /etc/rc.d/jail script,
configured by jail_* variables of the rc.conf file. When jail is
called by the /etc/rc.d/jail script, the default configuration
uses "-l -U root", and it is thus not vulnerable.
In some FreeBSD jail usage cases, an attacker inside the jail can
therefore access to an external directory.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/FreeBSD-directory-access-via-jail-9671