Vigil@nce - Linux kernel: privilege escalation via setxattr
October 2016 by Vigil@nce
This bulletin was written by Vigil@nce : https://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
A local attacker can use setxattr() on the Linux kernel, in order
to escalate his privileges.
Impacted products: Linux.
Severity: 2/4.
Creation date: 26/08/2016.
DESCRIPTION OF THE VULNERABILITY
The Linux kernel implements the setxattr() system call, which is
used to set extended attributes.
However, if setxattr() is called to set a POSIX ACL, and if the
user is not privileged, the sgid bit is not reset.
A local attacker can therefore use setxattr() on the Linux kernel,
in order to escalate his privileges.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
https://vigilance.fr/vulnerability/Linux-kernel-privilege-escalation-via-setxattr-20479