Technical Tip: Check the SSH encryption algorithm used on FortiGate using Nmap

[jiahoong112]

Description	This article describes how to check the SSH encryption algorithm on FortiGate using Nmap on Windows.
Scope	Any version of FortiGate. Changing the SSH Encryption Algorithm on FortiGate is only possible from v7.0.2 and above. Download Nmap for Windows here: https://nmap.org/download.html#windows To check the SSH encryption algorithm, the ssh2-enum-algos script will need to be downloaded: https://nmap.org/nsedoc/scripts/ssh2-enum-algos.html
Solution	Download the ssh2-enum-algos script. 'Right-click' on the download link and select 'Save Link As'. It will then be necessary to copy/paste this script into the nselibs folder of the NMap application. On Windows, paste the script into the following directory. Example file path: C:\Program Files (x86)\Nmap\nselib To test this, enable SSH on the FortiGate’s interface: On the Nmap application GUI, run this command to test: nmap --script ssh2-enum-algos x.x.x.x  <-----  x.x.x.x is the FortiGate interface IP where the SSH has been enabled and wants to test. The output should look like this: To only use certain encryption algorithms for SSH: In this situation, specify FortiGate to only use aes256-ctr. Here are the results on Nmap with regard to that: This is how the Nmap results look like if SSH is Disabled on the interface. No results returned: