Remediation Steps

Follow the steps below to remediate this finding on Linux (Debian/Ubuntu).

1. Block ICMP timestamp requests using iptables or nftables.

2. With iptables:

   sudo iptables -A INPUT -p icmp --icmp-type timestamp-request -j DROP
   sudo iptables -A OUTPUT -p icmp --icmp-type timestamp-reply -j DROP

3. To persist across reboots:

   sudo apt install iptables-persistent
   sudo netfilter-persistent save

4. With nftables:

   nft add rule inet filter input icmp type timestamp-request drop