STIGQter: STIG Summary: Red Hat Enterprise Linux 8 Security Technical Implementation Guide Version: 1 Release: 2 Benchmark Date: 23 Apr 2021:

RHEL 8 must prevent Internet Control Message Protocol (ICMP) redirect messages from being accepted.

DISA Rule

SV-230535r627750_rule

Vulnerability Number

V-230535

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

RHEL-08-040210

Severity

CAT II

CCI(s)

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

Weight

10

Fix Recommendation

Configure RHEL 8 to prevent ICMP redirect messages from being accepted with the following command:

$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0

$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0

If "0" is not the system's default value then add or update the following line in the appropriate file under "/etc/sysctl.d":

net.ipv4.conf.default.accept_redirects=0

net.ipv6.conf.default.accept_redirects=0

Check Contents

Verify RHEL 8 will not accept ICMP redirect messages.

Note: If either IPv4 or IPv6 is disabled on the system, this requirement only applies to the active internet protocol version.

Check the value of the default "accept_redirects" variables with the following command:

$ sudo sysctl net.ipv4.conf.default.accept_redirects net.ipv6.conf.default.accept_redirects

net.ipv4.conf.default.accept_redirects = 0
net.ipv6.conf.default.accept_redirects = 0

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

Vulnerability Number

V-230535

Documentable

False

Rule Version

RHEL-08-040210

Severity Override Guidance

Verify RHEL 8 will not accept ICMP redirect messages.

Note: If either IPv4 or IPv6 is disabled on the system, this requirement only applies to the active internet protocol version.

Check the value of the default "accept_redirects" variables with the following command:

$ sudo sysctl net.ipv4.conf.default.accept_redirects net.ipv6.conf.default.accept_redirects

net.ipv4.conf.default.accept_redirects = 0
net.ipv6.conf.default.accept_redirects = 0

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

Check Content Reference

M

Target Key

2921

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