Actu
Vigil@nce - Linux kernel: weakness of ASLR via mmap_rnd
February 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can use a weakness of ASLR of the Linux kernel, in
order to more easily guess a memory address.
Impacted products: Linux
Severity: 1/4
Creation date: 18/02/2015
DESCRIPTION OF THE VULNERABILITY
Systems use ASLR in order to randomize memory addresses used by
programs and libraries.
The mmap_rnd() function of the /arch/arm64/mm/mmap.c file
randomizes mmapped addresses. However, it uses a shift of one bit
on a mask, so one bit of random is lost. An attacker thus have two
more chances to bypass ASLR (131072 values, instead of 262144).
An attacker can therefore use a weakness of ASLR of the Linux
kernel, in order to more easily guess a memory address.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Linux-kernel-weakness-of-ASLR-via-mmap-rnd-16214
