SV-230537r1017299_rule
V-230537
SRG-OS-000480-GPOS-00227
RHEL-08-040230
CAT II
10
Configure RHEL 8 to not respond to IPv4 ICMP echoes sent to a broadcast address.
Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory:
net.ipv4.icmp_echo_ignore_broadcasts=1
Remove any configurations that conflict with the above from the following locations:
/run/sysctl.d/*.conf
/usr/local/lib/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
/lib/sysctl.d/*.conf
/etc/sysctl.conf
/etc/sysctl.d/*.conf
Load settings from all system configuration files with the following command:
$ sudo sysctl --system
Verify RHEL 8 does not respond to ICMP echoes sent to a broadcast address.
Check the value of the "icmp_echo_ignore_broadcasts" variable with the following command:
$ sudo sysctl net.ipv4.icmp_echo_ignore_broadcasts
net.ipv4.icmp_echo_ignore_broadcasts = 1
If the returned line does not have a value of "1", a line is not returned, or the retuned line is commented out, this is a finding.
Check that the configuration files are present to enable this network parameter.
$ sudo grep -r net.ipv4.icmp_echo_ignore_broadcasts /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf
/etc/sysctl.d/99-sysctl.conf: net.ipv4.icmp_echo_ignore_broadcasts = 1
If "net.ipv4.icmp_echo_ignore_broadcasts" is not set to "1", is missing or commented out, this is a finding.
If conflicting results are returned, this is a finding.
V-230537
False
RHEL-08-040230
Verify RHEL 8 does not respond to ICMP echoes sent to a broadcast address.
Check the value of the "icmp_echo_ignore_broadcasts" variable with the following command:
$ sudo sysctl net.ipv4.icmp_echo_ignore_broadcasts
net.ipv4.icmp_echo_ignore_broadcasts = 1
If the returned line does not have a value of "1", a line is not returned, or the retuned line is commented out, this is a finding.
Check that the configuration files are present to enable this network parameter.
$ sudo grep -r net.ipv4.icmp_echo_ignore_broadcasts /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf
/etc/sysctl.d/99-sysctl.conf: net.ipv4.icmp_echo_ignore_broadcasts = 1
If "net.ipv4.icmp_echo_ignore_broadcasts" is not set to "1", is missing or commented out, this is a finding.
If conflicting results are returned, this is a finding.
M
2921