UCF STIG Viewer Logo

The system must not accept ICMPv4 secure redirect packets by default.


Overview

Finding ID Version Rule ID IA Controls Severity
V-217919 RHEL-06-000090 SV-217919r505923_rule Medium
Description
Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.
STIG Date
Red Hat Enterprise Linux 6 Security Technical Implementation Guide 2020-09-03

Details

Check Text ( C-19400r376772_chk )
The status of the "net.ipv4.conf.default.secure_redirects" kernel parameter can be queried by running the following command:

$ sysctl net.ipv4.conf.default.secure_redirects
net.ipv4.conf.default.secure_redirects = 0

$ grep net.ipv4.conf.default.secure_redirects /etc/sysctl.conf /etc/sysctl.d/*
net.ipv4.conf.default.secure_redirects = 0

If "net.ipv4.conf.default.secure_redirect" 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.
Fix Text (F-19398r376773_fix)
To set the runtime status of the "net.ipv4.conf.default.secure_redirects" kernel parameter, run the following command:

# sysctl -w net.ipv4.conf.default.secure_redirects=0

Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" or a config file in the /etc/sysctl.d/ directory (or modify the line to have the required value):

net.ipv4.conf.default.secure_redirects = 0

Issue the following command to make the changes take effect:

# sysctl --system