AlmaLinux OS 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-269422 | SRG-OS-000132-GPOS-00067 | ALMA-09-040720 | SV-269422r1050305_rule | 2025-02-20 | 1 |
| Description |
|---|
| Loading and accessing the packet filters programs and maps using the bpf() system call has the potential of revealing sensitive information about the kernel state. |
| ℹ️ Check |
|---|
| Verify AlmaLinux OS 9 prevents privilege escalation thru the kernel by disabling access to the bpf system call with the following commands: $ sysctl kernel.unprivileged_bpf_disabled kernel.unprivileged_bpf_disabled = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ /usr/lib/systemd/systemd-sysctl --cat-config | egrep -v '^(#|;)' | grep -F kernel.unprivileged_bpf_disabled | tail -1 kernel.unprivileged_bpf_disabled = 1 If "kernel.unprivileged_bpf_disabled" is not set to "1", or nothing is returned, this is a finding. |
| ✔️ Fix |
|---|
| Configure AlmaLinux OS 9 to prevent privilege escalation through the kernel by disabling access to the bpf syscall with the following command: $ echo "kernel.unprivileged_bpf_disabled = 1" > /etc/sysctl.d/60-bpf.conf Load settings from all system configuration files with the following command: $ sysctl --system |