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V-253113

CAT II (Medium)

TOSS must disable access to network bpf syscall from unprivileged processes.

Rule ID

SV-253113r991589_rule

STIG

Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide

Version

V2R5

CCIs

CCI-000366

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 Content

Verify TOSS prevents privilege escalation thru 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 Text

Configure TOSS to prevent privilege escalation thru 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 need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command:

$ sudo sysctl --system