Enable ExecShield via sysctl
An XCCDF Rule
Description
By default on Red Hat Enterprise Linux 7 64-bit systems, ExecShield is
enabled and can only be disabled if the hardware does not support
ExecShield or is disabled in /etc/default/grub.
Rationale
ExecShield uses the segmentation feature on all x86 systems to prevent execution in memory higher than a certain address. It writes an address as a limit in the code segment descriptor, to control where code can be executed, on a per-process basis. When the kernel places a process's memory regions such as the stack and heap higher than this address, the hardware prevents execution in that address range. This is enabled by default on the latest Red Hat and Fedora systems if supported by the hardware.
- ID
- xccdf_org.ssgproject.content_rule_sysctl_kernel_exec_shield
- Severity
- Medium
- References
- Updated
Remediation - Ansible
- name: Check noexec argument exists
command: grep '^GRUB_CMDLINE_LINUX=.*noexec=.*"' /etc/default/grub
failed_when: false
register: argcheck
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
Remediation - Shell Script
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*noexec=.*"' '/etc/default/grub' ; then
sed -i 's/\(^GRUB_CMDLINE_LINUX=".*\)noexec=?[^[:space:]]*\(.*"\)/\1 \2/' '/etc/default/grub'