The Photon operating system must not respond to IPv4 Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-256568 | SRG-OS-000480-GPOS-00227 | PHTN-30-000099 | SV-256568r991589_rule | 2024-12-16 | 1 |
Description
Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.
ℹ️ Check
At the command line, run the following command:
# /sbin/sysctl -a --pattern ignore_broadcasts
Expected result:
net.ipv4.icmp_echo_ignore_broadcasts = 1
If the output does not match the expected result, this is a finding.
✔️ Fix
At the command line, run the following commands:
# sed -i -e "/^net.ipv4.icmp_echo_ignore_broadcasts/d" /etc/sysctl.conf
# echo net.ipv4.icmp_echo_ignore_broadcasts=1>>/etc/sysctl.conf
# /sbin/sysctl --load