Tuesday, April 8, 2014

Securing 4690 POS Terminals with PKI

Point of Sale (POS) terminals, communicate not only to all of the cash registers of a store, but also to central location. In order to secure this particular type of communication, and secure other items on the terminals as well, you need to add keys and certificates managed by a PKI.
To enable POS terminals to enroll for certificates specifically against an EJBCA® Enterprise PKI server, C2 Company and PrimeKey have successfully installed and used the EJBCA Enterprise clientToolBox on several Toshiba 4690 POS terminals.

About POS and Toshiba 4690

Commonly used in POS terminals, the Toshiba 4690 is an operating system which is basically IBM Java and DOS based, using specific 4690 DOS commands. So, if you are used to common computing with Linux or Windows, the Toshiba will appear a bit alien. However, taking the trouble to introduce PKI to the POS system, will enable any user of the 4690 terminals to trade on both strong authentication and encryption.

Steps to Enroll and Renew Certificates

Having IBM Java on board, helped us run EJBCA clientToolBox on Toshiba 4690, and made it possible to enroll and manage certificates. The Toshiba required some figuring out of which new commands to run, but once that was (elegantly) performed by C2, EJBCA clientToolBox was running ever so nicely.
The following steps are only a single example of how you can use the certificate management capability on POS terminals. In fact, there are limitless possibilities.
Use the Native DOS commands to generate keys and CSRs. Once those are generated you can enroll for a certificate against EJBCA, using clientToolBox.
To enroll new terminals for the first time when they are installed in a store, you can use a pre-installed certificate on the POS terminal image. To enroll for the real terminal certificate you use the pre-istalled certificate temporarily, to enable access from the POS terminal to EJBCA. The pre-installed certificate does not need any admin access in the EJBCA system. Do the following:
  • Install a new POS terminal with an image, including a pre-installed communication certificate on the image.
  • Register the POS terminal (with serial number or similar) in EJBCA, and you'll receive a one-time enrollment code.
  • Generate keys and a CSR (to the csr.pem file) on the POS terminal, by using DOS commands.
  • Submit the CSR to EJBCA, to get the signed certificate back, using this command:
./ejbcaClientToolBox.sh EjbcaWsRaCli pkcs10req terminalSerial enrollmentCode csr.pem PEM NONE certificate.pem
Now you are ready to remove the pre-installed communication certificate from the image, to finally make the image secure, only by its rightful individual certificate. However, to block the POS terminal from accessing store systems (in case the terminal gets stolen or hacked) the latter step can be revoked.
A single PKI administrator action is found in the above work-flow; registering the POS terminal in EJBCA. This is done in order to authenticate the initial enrollment and make sure that no unauthorized terminal receives real certificates, that is, illegitimate access to store systems. With the final certificate installed, the terminal can automatically renew it before expiry, requiring no PKI administrator action during daily operations.

More information

Fore more information, or to get in touch with C2 for help with securing your POS terminals, contact Chris or me. Cheers!
Chris Chu
chris at c2company.com
Tomas Gustavsson
tomas at primekey.se

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