TOSS 5 must disable access to network bpf system call from nonprivileged processes.

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.

Verify TOSS 5 prevents privilege escalation through the kernel by disabling access to the bpf system call using the following command:

$ 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.

Configure TOSS 5 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