Technical Tip: Block ICMP timestamp on FortiGate interface while keeping ping enabled

ppatel · ‎01-25-2022

Description

This article describes Block ICMP timestamp on Fortigate interface while keeping ping enabled.

The ICMP timestamp response from Fortigate contains device's date and time. This information could be used as a vulnerability with high visibility.

To block ICMP timestamp request on wan1 interface IP, follow the below steps:

# config system interfac

edit "wan1"

set vdom "root"

set ip 1.1.1.1 255.255.255.0

set allowaccess ping

set type physical

set snmp-index 1

Scope

Solution

1) Create a firewall service for ICMP type 13 (timestamp request):

# config firewall service custo

edit "TIMESTAMP"

set protocol ICMP

set icmptype 13

2) Create address entry for wan1 interface IP:

# config firewall addres

edit "wan1-IP"

set subnet 1.1.1.1 255.255.255.255

3) Create local-in-policy to block timestamp requests on wan1 interface IP:

# config firewall local-in-polic

edit 1

set intf "wan1"

set srcaddr "all"

set dstaddr "wan1-IP"

set service "TIMESTAMP"

set schedule "always"

set action deny