STIGQter: STIG Summary: Oracle Linux 7 Security Technical Implementation Guide Version: 2 Release: 3 Benchmark Date: 23 Apr 2021:

The Oracle Linux operating system must ignore Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages.

DISA Rule

SV-221879r603260_rule

Vulnerability Number

V-221879

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

OL07-00-040641

Severity

CAT II

CCI(s)

• CCI-000366 - The organization implements the security configuration settings.

Weight

10

Fix Recommendation

Set the system to ignore IPv4 ICMP redirect messages 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.all.accept_redirects = 0

Issue the following command to make the changes take effect:

# sysctl --system

Check Contents

Verify the system ignores IPv4 ICMP redirect messages.

# grep 'net.ipv4.conf.all.accept_redirects' /etc/sysctl.conf /etc/sysctl.d/*

If "net.ipv4.conf.all.accept_redirects" 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_redirects" variables with the following command:

# /sbin/sysctl -a | grep 'net.ipv4.conf.all.accept_redirects'

net.ipv4.conf.all.accept_redirects = 0

If the returned line does not have a value of "0", this is a finding.

Vulnerability Number

V-221879

Documentable

False

Rule Version

OL07-00-040641

Severity Override Guidance

Verify the system ignores IPv4 ICMP redirect messages.

# grep 'net.ipv4.conf.all.accept_redirects' /etc/sysctl.conf /etc/sysctl.d/*

If "net.ipv4.conf.all.accept_redirects" 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_redirects" variables with the following command:

# /sbin/sysctl -a | grep 'net.ipv4.conf.all.accept_redirects'

net.ipv4.conf.all.accept_redirects = 0

If the returned line does not have a value of "0", this is a finding.

Check Content Reference

M

Target Key

4089

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