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Vigil@nce - Linux kernel: sandbox like escape via remount
August 2014 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can remove the restrictions of a filesystem mount, in
order to escalate his privileges.
Impacted products: Linux
Severity: 1/4
Creation date: 14/08/2014
DESCRIPTION OF THE VULNERABILITY
The Linux kernel allows mounting a filesystem and ignoring or
forbidding features like device files or set-uid/set-gid programs.
This may be used with system calls like chroot(2) to limit the
abilities of a process that must run as "root".
The mount may be mimited to a subtree instead of a whole
filesystem. However, in this case, a process running under "root"
UID can remount the subtree and removing the restrictions of the
initial mount.
An attacker can therefore remove the restrictions of a filesystem
mount, in order to escalate his privileges.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Linux-kernel-sandbox-like-escape-via-remount-15182
