Add Firepower Management Center Certificate using CLI

-

In this article I want to demonstrate how too add signed certificates to the Firepower Management Center (FMC) using the CLI.


If you've worked with the FMC for some time, you'll know that the GUI can be quite limited when it comes to the sort of information you enter before generating a CertificateCSR.

In fact a particular use case for wanting to use the CLI to generate CSR's for the FMC is when you want to issue the same certificate to more than one FMC. As it stands today there isn't a way to accommodate this use case via the GUI an although possible, this request can only be fulfilled by using the CLI.

With that, in this article we will focus on how we can fulfill the mentioned requirement and have one certificate issued for more than one FMC.

We will have our internal CA (Microsoft Server) issue an internal signed certificate that will be imported to both FMC's.

Demonstration Hardware & Versions


  • Microsoft Server 2019 (CA Server)
  • Firepower Management Center version 6.5
Note: You will require CLI root access to the FMC and admin access to the CA

Populate Certificate Fields


The important part of the configuration below is to populate the common name with a generic name and use the Subject Alternative Name (SAN) field to populate the FDQN names of the FMC's.

Access the CLI of each FMC and enter the following commands in order to populate the certificate fields before generating a CSR. You will need to carry out the following tasks on both FMC's.

Note: This article assumes the reader has knowledge of Linux
expert
sudo su #enter admin password#
cd /etc/ssl
vim fmccert.cnf

#Enter the below configuration and populate where necessary#

[ req ]
default_bits = 2048
distinguished_name = req_distinguished_name
req_extensions = req_ext
prompt = no
[ req_distinguished_name ]
countryName = #ENTER INFORMATION#
stateOrProvinceName = #ENTER INFORMATION#
localityName = #ENTER INFORMATION#
organizationName = #ENTER INFORMATION#
commonName = #ENTER INFORMATION#
[ req_ext ]
subjectAltName = @alt_names
[alt_names]
DNS.1 = fmc1.cciesecuritylab.co.uk
DNS.2 = fmc2.cciesecuritylab.co.uk

Save the file once completed and check that the file has been created successfully by entering the following commands.
cat fmccert.cnf

Generate CSR's


Once the certificate fields have been populated, generate the CSR from each FMC by entering the following configurations.
openssl req -out fmc.csr -key server.key -config fmccert.cnf -new

Copy CSR


Copy the contents of the CSR to a notepad. The contents of the certificate request will be required to sign the FMC's.
cat fmc.csr

Sign the FMC's using via the CA

In this demonstration we use Microsoft Server 2019 as a CA. A demonstration of these steps will be covered in the video demonstration at the bottom of the screen.

Once signed, export the BASE 64 certificate contents ready to paste onto the CLI of the FMC's.

Copy Signed Certificates to FMC's


On the FMC's we will now replace /etc/ssl/server.cert with the contents of our new signed certificate. Use the following command to replace the contents of the file with the newly signed certificate.
vim server.crt

Warning: Be careful not to modify 'server.key' otherwise you may need to regenerate a new RSA public/private key pair.

Restart & Test HTTPS service


Once the content of the above file has been changed, the https service needs to be restarted. Enter the following configuration in order to restart and verify the httpd service.
pmtool restartbyid httpsd

pmtool status | grep https

#The following is an example of what you should see#
httpsd (system,gui) - Running 31632
Command: /usr/bin/httpsd -D FOREGROUND
PID File: /var/run/httpsd.pid

Once the service has been verified as running, test GUI access and verify that the certificate presented is correct.

In the following screenshot you can see that the FMC used for this demonstration now has the SAN field populated.


You can also view the issued certificate by logging into the FMC GUI and navigating to System > Configuration > HTTPS Certificate as shown in the screenshot below.


Other observations


I've noticed that GUI access is stuck when powering off the FMC without gracefully shutting it down. The message presented when attempting to access the GUI is: 'System processes are starting, please wait.' To fix this, you may need to restart those processes too using the following commands:

View the status of the GUI processes:
pmtool status | grep -i gui

Restart the GUI processes:
/etc/rc.d/init.d/console restart"


For a video demonstration, please see the video below.














Kelvin Charles - Network and Cyber Security Professional.

Popular Posts

Capturing EAPOL and RADIUS Using Wireshark

-
Image
In this article we are going to take a look at how to capture Extensible Authentication Protocol Over LAN (EAPOL) and Remote Authentication Dial-In User Service (RADIUS) packets using Wireshark. This article can be useful for troubleshooting 802.1x within your environment and can also be used for learning purposes. The following topology has been used to gather the required output for this article. Note: This article will only cover the switch configurations that are required to gather EAPOL and RADIUS configuration. Overview of the Topology The supplicant is configured to perform 802.1x using EAP-TLS as the authentication method The user certificate on the supplicant will be used for authentication The supplicant has Wireshark installed Cisco ISE is used for authentication and authorisation The supplicant is assigned to VLAN 10 upon authentication and all other endpoint ports are assigned to VLAN 99 Sniffer device is running Wireshark in order to capture RADIUS flows via SPAN 802.1x
Read more

Configuring Cisco Smart License Software

-
In this article, I would like to demonstrate how to configure Cisco Smart Licensing on the virtual Cisco Adaptive Security Appliance (ASAv). This post assumes that readers already have access to there own Smart Account and would like to know the process of applying licenses. Step 1: Generate ID Token Sign into your Cisco Software Portal: software.cisco.com and navigate to “Smart Software Licensing” You will now need to create an ID token for your device, this is required for communication between the device and the licensing authority. Follow the steps below to create a new token. Click Inventory >>> General >>> New Token and select your preferred options and enter a description for your token. Once you are happy with your token settings click Create Token . You should now have a token created which can be copied over to the device you wish to license. All commands and output from this point will be related to the ASA so please seek out further advice if you wish
Read more

Cisco :: FXOS Authentication Using TACACS

-
In this article, I will describe how to enable authentication and authorization for Firepower eXtensible Operating System (FXOS) devices. The use case presented in this document illustrates how Cisco Identity Services Engine (ISE) can be utilised with attribute-value pairs (AV-Pairs) to authenticate and authorize users accessing the Firepower Chassis Manager (FCM) or FXOS platforms via TACACS+. At the time of writing this post, I found that limited documentation existed and of that documentation that did exist, the examples given weren’t as straightforward. In an effort to make this process easier for my colleagues and customers to understand I have put together the following instructions based on a previous use case given to me. Extracts of this document have been taken from a wider document I am currently creating. I will update this article with the complete document when it has been finalized. Requirements A ‘Device Administration’ license is required in order to use TACACS+ with
Read more

Configuring Remote Access VPN on Firepower

-
Image
In this article we are going to take a look at how to configure remote access VPN's on Firepower devices. This demonstration is based on the following lab environment: Cisco Virtual Firepower Management Center Cisco Virtual Firepower Threat Defense Cisco ISE 2.6 Windows host with AnyConnect VPN Windows Server 2019 (CA Server) All Firepower devices are running version 6.5 Note: ISE is used for authentication and authorization in the following lab however the configuration elements of ISE are out of scope for this demonstration. Generate a CSR for Remote Access VPN's Those accessing your network remotely need to trust the service you're running. Without the correct trust users could face issues connecting via VPN. With access to the FMC navigate to Objects > Object Management > PKI > Cert Enrollment Assuming you are opting for manual enrollment, select 'Manual' in Enrollment Type and copy the CA Certificate BASE-64 into the field. Now select the 'Certifi
Read more

Kali Linux :: CAM Table Overflow Attack Demonstration

-
Image
As part of my on-going studying for the CCNA Security 210 – 260 certification I have been exploring different types of network attacks, one of which is CAM table overflow attacks. In this article I would like to share what I have learnt and provide a demonstration of the attack carried out in a lab environment. To understand my demonstration, you first need to understand how a CAM table overflow attack works and what happens as a result of the attack.   Switches build Content Addressable Memory (CAM) tables based on mac-addresses and port numbers. When a switch receives a frame it checks the table to see if the source mac-address is already known, if the source mac-address is unknown the switch will add the mac-address to the table along with the port number. The switch then checks the destination layer two frame and if no entry exists the switch broadcasts the frame out of all ports except the port in which the frame was received. Presuming the destination mac-address wants to respond
Read more