Can I use CA Root Certificate for Debrypting SSL Traffic?

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Can I use CA Root Certificate for Debrypting SSL Traffic?

L1 Bithead

Hello,

 

I want o start setting using Decryption Policy, to Decrypt & Intercept SSL (443) traffic from users when connecting to Internet.

 

I am wondering, can I use one of the well known Certificate Trusted, e.g., Global Sign by installing it on the Palo Alto  without installing the certificate manually on the users' computers?!

 

Thank you ...

1 ACCEPTED SOLUTION

Accepted Solutions

Cyber Elite
Cyber Elite

@mshamsan 

 

You can not use external third party for ssl decryption as you need private keys of the 3rd party to issue your own certs.

You need your Internal CA for this which your pc can trust.

 

I have seen some clients they have their internal CA. Root on their computers.

From Internal Root CA you can create your ssl decryption certificate.

 

OR 

 

You can create a self signed cert on the firewall then you need to import that on all  computers if you do not have Internal CA.

 

Regards

MP

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4 REPLIES 4

Cyber Elite
Cyber Elite

@mshamsan 

 

You can not use external third party for ssl decryption as you need private keys of the 3rd party to issue your own certs.

You need your Internal CA for this which your pc can trust.

 

I have seen some clients they have their internal CA. Root on their computers.

From Internal Root CA you can create your ssl decryption certificate.

 

OR 

 

You can create a self signed cert on the firewall then you need to import that on all  computers if you do not have Internal CA.

 

Regards

MP

Hi MP18,

 

Thank you for the clarifications, actually that the same understanding but one of the Palo Alto documents confused me, when talking about using sort of External certificate to avoid installing the certificate on the end users' hosts!

 

My aim was to avoid installing anything on the PCs and Smart Phones, iPad used by the users.

 

Regards,

Hi @mshamsan ,

You probably confusing Inbound SSL decryption and Forward SSL decryption.

- With Inbound SSL decryption you are decrypting the traffic from public Internet to your public web server. In this case it is prefferable to have certificated that is signed by public trusted CA

- With Forward SSL decryption you are decrypting the traffic from your internal users to public Internet. In this case during the decryption FW is intercepting user traffic and "replace" the original server certificate with cert generated by the FW. This cert will be signed by the CA cert installed on the FW - either self signed or your private CA imported on the FW.

 

Imaging for a second that publicly trusted CA gives your their root/intermediate CA... Which means you will be able to create any server certificate you want and everyone on earth will trust you...Nothing will stop you to create certificate for "facebook.com", build your own web server with that certificate and start pretending you are Mark Zuckerberg

 

In summary - there is no way to have Forward SSL decryption (decrypt internal users to internet) without instally certificate on the user machine. If you have internal PKI it will be a lot easier for you, but if you don't you must to it manually or with some kind of scripting.

 

 

Cyber Elite
Cyber Elite

Hello,

You can use an internal subordinate certificate that your workstations already trust since its from your internal CA.

 

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClWOCA0

 

Cheers!

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