Ensure address space layout randomization (ASLR) is enabled

MediumLevel 1Automatedros

Description

Address space layout randomization (ASLR) is an exploit mitigation technique which randomly arranges the address space of key data areas of a process. The audit requires the running value and the persisted sysctl setting to be 2. Host-level control from the CIS ROS Melodic benchmark (Ubuntu 18.04 robot hosts); run as root.

How it is checked

Audit method: Shell command

shell

bad=0
chk() { case $1 in net.ipv6.*) [ -d /proc/sys/net/ipv6 ] || return 0 ;; esac
  v=$(sysctl -n "$1" 2>/dev/null) || { echo "$1: not readable"; bad=1; return; }
  [ "$v" = "$2" ] || { echo "$1 = $v (expected $2)"; bad=1; }
  p=$(awk -F= -v k="$1" '{gsub(/^[ \t]+|[ \t]+$/, "", $1)} $1 == k {v = $2} END {gsub(/[ \t]/, "", v); print v}' /etc/sysctl.conf /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf 2>/dev/null)
  [ "$p" = "$2" ] || { echo "$1 not persisted as $2 in sysctl configuration (${p:-unset})"; bad=1; }; }
chk kernel.randomize_va_space 2
[ "$bad" -eq 0 ] && echo compliant

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Set the following parameter in /etc/sysctl.conf or a /etc/sysctl.d/* file: kernel.randomize_va_space = 2 Run the following command to set the active kernel parameter: # sysctl -w kernel.randomize_va_space=2

Properties

Operating systems: Any
Tags: rosros1melodicsystem
Reference: CIS ROS Melodic Benchmark v1.0.0 - 1.6.2 Ensure address space layout randomization (ASLR) is enabled

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target ros