IPsec dial-up in aggressive mode or on a shared pre-shared key alone
At a glance
Base severity
Area
Platform
Evidence level
Benchmark reference
Reads the export, not the device
ConfigProof reads a configuration export. This control is evaluated against the objects in that file, and it reports what the file says. It does not connect to the device and sees no traffic, so a finding here describes the configuration, not what the firewall is doing right now.
Why it matters
Aggressive mode sends the peer identity and part of the exchange in clear text. A gateway that the shared pre-shared key alone opens, with no peer identity and no user login, lets anyone who learns the key join the VPN.
How to fix it
Web interface
The steps below are written for the web interface. A finding raised on your own export carries the same steps with your object names filled in.
- Use main mode, and require a user login (xauthtype or EAP with a user group) or certificates on the dial-up gateway.
Command line
FortiOS CLI
config vpn ipsec phase1-interfaceedit <dialup-phase1-name>set mode mainset xauthtype autoset authusrgrp <user-group>nextend
An example. Values in angle brackets are yours to supply; a finding on your own export fills in the names it read. FortiOS saves a change when you type next or end, with no separate commit. Read every line first.
Read it back
show vpn ipsec phase1-interfaceValues to fill in2
- <dialup-phase1-name>
- The name of the dial-up IPsec entry
- <user-group>
- The user group allowed to use the dial-up tunnel
Before you type it2
- Written from the FortiOS CLI Reference, not yet run on a device. Read each line before typing it.
- On a device with VDOMs, type these inside the VDOM (config vdom, edit the VDOM) or inside config global for a global setting.
How to confirm the fix
- Connect a FortiClient with a valid user and confirm one with only the key is refused.
Limits
- No limitation is recorded for this control beyond the one that applies to all of them: it reads a configuration export.
Compliance references
No benchmark recommendation is mapped to this control in this version.
See it on your own firewall
One complete analysis of one firewall costs nothing and needs no card.