UCF STIG Viewer Logo
Changes are coming to https://stigviewer.com. Take our survey to help us understand your usage and how we can better serve you in the future.
Take Survey

The Oracle Linux operating system must not forward Internet Protocol version 4 (IPv4) source-routed packets by default.


Overview

Finding ID Version Rule ID IA Controls Severity
V-221876 OL07-00-040620 SV-221876r603260_rule Medium
Description
Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router.
STIG Date
Oracle Linux 7 Security Technical Implementation Guide 2022-09-07

Details

Check Text ( C-23591r419700_chk )
Verify the system does not accept IPv4 source-routed packets by default.

# grep net.ipv4.conf.default.accept_source_route /etc/sysctl.conf /etc/sysctl.d/*
net.ipv4.conf.default.accept_source_route = 0

If "net.ipv4.conf.default.accept_source_route" is not configured in the /etc/sysctl.conf file or in the /etc/sysctl.d/ directory, is commented out, or does not have a value of "0", this is a finding.

Check that the operating system implements the accept source route variable with the following command:

# /sbin/sysctl -a | grep net.ipv4.conf.default.accept_source_route
net.ipv4.conf.default.accept_source_route = 0

If the returned line does not have a value of "0", this is a finding.
Fix Text (F-23580r419701_fix)
Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" or a configuration file in the /etc/sysctl.d/ directory (or modify the line to have the required value):

net.ipv4.conf.default.accept_source_route = 0

Issue the following command to make the changes take effect:

# sysctl --system