RHEL 9 must disable access to network bpf system call from nonprivileged processes.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-257810	SRG-OS-000132-GPOS-00067	RHEL-09-213075	SV-257810r1155712_rule	2025-11-24	2

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 lexicographical order, regardless of the directories in which they reside. 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 Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000480-GPOS-00227

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 lexicographical order, regardless of the directories in which they reside. 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 Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000480-GPOS-00227

ℹ️ Check
Verify RHEL 9 prevents privilege escalation through the kernel by disabling access to the bpf system call. Check the status of the "kernel.unprivileged_bpf_disabled" kernel parameter with the following command: $ sysctl kernel.unprivileged_bpf_disabled kernel.unprivileged_bpf_disabled = 1 If "kernel.unprivileged_bpf_disabled" is not set to "1", or is missing, this is a finding.

✔️ Fix
Configure RHEL 9 to prevent privilege escalation through the kernel by disabling access to the bpf system call. Create the drop-in file if it does not already exist: $ sudo vi /etc/sysctl.d/99-kernel_unprivileged_bpf_disabled.conf Add the following line to the file: kernel.unprivileged_bpf_disabled = 1 Reload settings from all system configuration files with the following command: $ sudo sysctl --system

✔️ Fix

Configure RHEL 9 to prevent privilege escalation through the kernel by disabling access to the bpf system call. Create the drop-in file if it does not already exist: $ sudo vi /etc/sysctl.d/99-kernel_unprivileged_bpf_disabled.conf Add the following line to the file: kernel.unprivileged_bpf_disabled = 1 Reload settings from all system configuration files with the following command: $ sudo sysctl --system