RHEL 8 must disable the kernel.core

RHEL 8 must disable the kernel.core_pattern.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-230311	RHEL-08-010671	SV-230311r858769_rule		Medium

Description
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/.conf /run/sysctl.d/.conf /usr/local/lib/sysctl.d/.conf /usr/lib/sysctl.d/.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Description

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

STIG	Date
Red Hat Enterprise Linux 8 Security Technical Implementation Guide	2023-03-08

Details

Check Text ( C-32980r833304_chk )
Verify RHEL 8 disables storing core dumps with the following commands: $ sudo sysctl kernel.core_pattern kernel.core_pattern = \|/bin/false If the returned line does not have a value of "\|/bin/false", or a line is not returned and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.core_pattern /run/sysctl.d/.conf /usr/local/lib/sysctl.d/.conf /usr/lib/sysctl.d/.conf /lib/sysctl.d/.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.core_pattern = \|/bin/false If "kernel.core_pattern" is not set to "\|/bin/false", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Check Text ( C-32980r833304_chk )

Verify RHEL 8 disables storing core dumps with the following commands:

$ sudo sysctl kernel.core_pattern

kernel.core_pattern = |/bin/false

If the returned line does not have a value of "|/bin/false", or a line is not returned and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Check that the configuration files are present to enable this kernel parameter.

$ sudo grep -r kernel.core_pattern /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf

/etc/sysctl.d/99-sysctl.conf:kernel.core_pattern = |/bin/false

If "kernel.core_pattern" is not set to "|/bin/false", is missing or commented out, this is a finding.

If conflicting results are returned, this is a finding.

Fix Text (F-32955r858768_fix)
Configure RHEL 8 to disable storing core dumps. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: kernel.core_pattern = \|/bin/false Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/.conf /usr/local/lib/sysctl.d/.conf /usr/lib/sysctl.d/.conf /lib/sysctl.d/.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

Fix Text (F-32955r858768_fix)

Configure RHEL 8 to disable storing core dumps.

Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory:

kernel.core_pattern = |/bin/false

Remove any configurations that conflict with the above from the following locations:
/run/sysctl.d/*.conf
/usr/local/lib/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
/lib/sysctl.d/*.conf
/etc/sysctl.conf
/etc/sysctl.d/*.conf

The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command:

$ sudo sysctl --system