Vulnerability Discussion

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.

Check

Verify OL 8 prevents privilege escalation through the kernel by disabling access to the "bpf" syscall with the following commands:

$ sudo 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.

Fix

Configure the system to prevent privilege escalation through the kernel by disabling access to the "bpf" syscall by adding the following line to a file in the "/etc/sysctl.d" directory:

kernel.unprivileged_bpf_disabled = 1

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

$ sudo sysctl --system