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V-274004

CAT II (Medium)

Amazon Linux 2023 must disable access to network bpf system call from nonprivileged processes.

Rule ID

SV-274004r1198253_rule

STIG

Amazon Linux 2023 Security Technical Implementation Guide

Version

V1R3

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 Amazon Linux 2023 prevents privilege escalation through the kernel by disabling access to the bpf system call 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 Amazon Linux 2023 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