TLS 1.3 support

[Jan_Linhart]

Hi everybody,

any news regarding change of decryption from passive to proxy mode to support TLS 1.3 decryption?

Thank you,

Jan

[Abdul_Razaq]

Hi @Jan_Linhart ,

Is below document addresses your query?

https://live.paloaltonetworks.com/t5/Customer-Advisories/Action-required-if-you-have-enabled-SSL-dec...

Added to above, As of my knowledge, PA will be doing proxy by default for all connections matching with forward proxy rule,

But inbound inspection is different, it was passive eveasdropping till PanOS 8.0, so if key exchange is DH/ECDH, the decryption fails before 8.0. But after 8.0 they changed the behaviour, so that PA will be active in MITM. if key exchange is RSA, PA wont be proxying the connection, but if key exchange is DH/ECDH, PA will involk the proxy module. 

[Jan_Linhart]

Hi Abdul,

unfortunately, there is no answer for my question. PAN-OS has support for TLS1.3 now, but not support for decryption.

Please look at this link:

https://blog.gigamon.com/2018/05/10/tls-1-3-is-moving-forward-what-you-need-to-know-today-to-get-rea...

Most important part is:

With TLS 1.3, this passive mode decryption (the one PANW is using - transparent for clients) will no longer be possible since the RSA key exchange has been removed. 

Jan

[Abdul_Razaq]

Hi @Jan_Linhart ,

PA is doing proxy for DH/ECDH key exchange now also. so if you have a PanOS version supports TLS 1.3, things should work i feel. 

Do you have a trustable source which says 'Pan OS wont support decryption for TLS 1.3' ?.

[Chacko42]

23.10.2018:

Dear valued Palo Alto Networks customer,

Please take the action recommended below if you have enabled SSL decryption forward proxy. This is required for users to access Gmail and other websites and applications using web browsers that implement strict TLS 1.3 compliance. We have been informed that Google Chrome is planning to implement strict TLS 1.3 compliance in their upcoming version 72. The stable build of Google Chrome version 72 may be available in January 2019, and if your users use a pre-stable build of Google Chrome, they will experience the issue outlined below earlier.

Applies to

All supported PAN-OS releases

Action Required

If you run PAN-OS 8.1:

• Upgrade to PAN-OS 8.1.4 (available now)

[Brandon_Wertz]

@Abdul_Razaq @Chacko42  I think what @Jan_Linhart  is asking is not so much about the ability for PAN-OS to just merely support the protocol, but rather the ability to actually DECRYPT the TLS1.3 session.

I think that it something that is being targeted for PAN-OS 9.1, but who knows if it'll actually make it in the release...

BTW this is another reason I bet Palo came out with the X2XX hardware.  I doubt the legacy HW would have been able to handle TLS1.3 decryption.

[Brandon_Wertz]

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@Abdul_Razaq wrote:

Hi @Jan_Linhart ,

Do you have a trustable source which says 'Pan OS wont support decryption for TLS 1.3' ?.

---

Yeah PAN-OS software itself.

[BPry]

So it's important to note here the difference between supporting the protocol and actively being able to decrypt TLS 1.3.

• Palo Alto has now added support for TLS1.3 and has made the required changes so that the firewall will no-longer attempt to decrypt TLS 1.3 traffic, which was causing issues for customers with decryption enabled running PAN-OS versions prior to 8.0.14 in the 8.0 code branch or 8.1.4 in the 8.1 code branch.
•  Palo Alto can't actually decrypt TLS1.3 traffic just yet and as @Brandon_Wertz mentioned it's something being targeted for a future update. Whether or not it actually makes it into 9.1 or not we'll have to wait and see. 

[Jan_Linhart]

Hi guys, 

as you wrote before - I'm aware of protocol support, but I was asking about plans for decryption support. It is not going to be easy at all and PANW will have to completely change decryption concept from "passive" to real proxy.

Jan

[Sec101]

ok, so did this one ever get answered?

[BPry]

@Sec101,

What exactly are you still wondering? The basis of this post still remains the same, PAN does not currently support the decryption of TLS1.3 traffic. 

[Sec101]

@BPry-Thank you for the quick reponse.   I didn't completely understand the fact that palo was supporting but not decrypting on this as of yet.  I think it was mentioned in this post, but I'm guessing most are eagerly awaiting hearing how this will work in the future, being transparent/explicit, or however it will work/if it will work...

From a pure security perspective, do you forsee more and more dependence on the endpoint logging and detection, and less and less from the firewall perspective moving forwared?  Without decryption, it seems like the ACC would be a block of SSL and dns.  

[BPry]

@Sec101,

I'm running under the assumption that there will be a break in time in which we need to follow current guidance and disable TLS1.3 on endpoints to ensure it only utilizes something that can be decrypted. 

From a pure fundamental standpoint decrypting TLS1.3 doesn't actually change, it's still very possible. The ability to passively decrypt the connection with a private key however does. PAN just needs to make some adjustments to the way they are decrypting traffic and this will function from a firewall level perfectly fine. This is already targeted for a public release in 9.1 (that could get pushed back), so until the time comes that you can install whatever release TLS1.3 decryption is enabled in, simply force your clients to fall back to 1.2.

[Chacko42]

@kiwi Can you post a statement to the current TLS 1.3 decryption situation?

[Brandon_Wertz]

---

@Chacko42 wrote:

@kiwi Can you post a statement to the current TLS 1.3 decryption situation?

---

Nothing has changed. 

Support of decrypting TLS versions will only come in the release of new PAN-OS versions other than patch updates (so X.X).  It wasn't supported on 8.0.X, it's not supported on 8.1.X nor is it supported on 9.0.X.  The community is currently waiting on a public release as to if it'll be support in 9.1.X or if even somtime in a future release.