{"description": "To disable IPv6 protocol support in the Linux kernel,\nadd the argument <tt>ipv6.disable=1</tt> to the default\nGRUB2 command line for the Linux operating system.\nTo ensure that <tt>ipv6.disable=1</tt> is added as a kernel command line\nargument to newly installed kernels, add <tt>ipv6.disable=1</tt> to the\ndefault Grub2 command line for Linux operating systems. Modify the line within\n<tt>/etc/default/grub</tt> as shown below:\n<pre>GRUB_CMDLINE_LINUX=\"... ipv6.disable=1 ...\"</pre>\nRun the following command to update command line for already installed kernels:<pre># update-grub</pre>", "rationale": "Any unnecessary network stacks, including IPv6, should be disabled to reduce\nthe vulnerability to exploitation.", "severity": "low", "references": {"pcidss": ["Req-1.3.1", "Req-1.3.2"]}, "control_references": {}, "components": [], "identifiers": {}, "ocil_clause": "IPv6 is not disabled", "ocil": "Inspect the form of default GRUB 2 command line for the Linux operating system\nin <tt>/etc/default/grub</tt>. If it includes <tt>ipv6.disable=1</tt>,\nthen the parameter will be configured for newly installed kernels.\nFirst check if the GRUB recovery is enabled:\n<pre>$ sudo grep 'GRUB_DISABLE_RECOVERY' /etc/default/grub</pre>\nIf this option is set to true, then check that a line is output by the following command:\n<pre>$ sudo grep 'GRUB_CMDLINE_LINUX_DEFAULT.*ipv6.disable=1.*' /etc/default/grub</pre>\nIf the recovery is disabled, check the line with\n<pre>$ sudo grep 'GRUB_CMDLINE_LINUX.*ipv6.disable=1.*' /etc/default/grub</pre>.Moreover, current Grub config file <tt>grub.cfg</tt> must be checked. The file can be found\neither in <tt>/boot/grub</tt> in case of legacy BIOS systems, or in <tt>/boot/grub</tt> in case of UEFI systems.\nIf they include <tt>ipv6.disable=1</tt>, then the parameter\nis configured at boot time.\n<pre>$ sudo grep vmlinuz GRUB_CFG_FILE_PATH | grep -v 'ipv6.disable=1'</pre>\nFill in <tt>GRUB_CFG_FILE_PATH</tt> based on information above.\nThis command should not return any output.", "oval_external_content": null, "fixtext": "", "checktext": "", "vuldiscussion": "", "srg_requirement": "", "warnings": [], "conflicts": [], "requires": [], "policy_specific_content": {}, "platform": "grub2", "platforms": ["grub2"], "sce_metadata": {}, "inherited_platforms": [], "cpe_platform_names": ["grub2"], "inherited_cpe_platform_names": [], "bash_conditional": null, "fixes": {}, "title": "Ensure IPv6 is disabled through kernel boot parameter", "definition_location": "/aptdata/openscap/scap-security-guide/linux_os/guide/system/network/network-ipv6/disabling_ipv6/grub2_ipv6_disable_argument/rule.yml", "template": {"name": "grub2_bootloader_argument", "vars": {"arg_name": "ipv6.disable", "arg_value": "1"}, "backends": {}}}