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V-282508

CAT II (Medium)

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

Rule ID

SV-282508r1200504_rule

STIG

Tri-Lab Operating System Stack (TOSS) 5 Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-001082

Discussion

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.

Check Content

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.

Fix Text

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