Decryption exception issue - no SNI - SCN: chat.signal.org

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Decryption exception issue - no SNI - SCN: chat.signal.org

L1 Bithead

Hi,

how to add following decryption error (ssl-forward-proxy) to exceptions?

 

- logs->decryption: dest address: ac88393aca5853df7.awsglobalaccelerator.com (shodan solves this ip /13.248.212.111/ also to service.signal.org; SNI - no value; SCN: chat.signal.org; error: General TLS protocol error

JarerkZajac_0-1655994017023.png

JarerkZajac_3-1655994196320.png

 

- logs->traffic: destination like above; decrypted: no; app: ssl; session end reason: decrypt-cert-validation; action: allow; type: end

JarerkZajac_1-1655994083091.png

 

What I have done:

- device->cert management->SSL decrypt exclusion: chat.signal.org and *.signal.org -> exclude from decryption

JarerkZajac_2-1655994143220.png

 

Other (almost all) exceptions work fine, but only this cert has no value for SNI (Server Name Indication).

JarerkZajac_7-1655994370894.png

 

1 ACCEPTED SOLUTION

Accepted Solutions

Cyber Elite
Cyber Elite

Hi @JarerkZajac ,

You can create Decryption rule, matching by destination address and using FQDN object with action set to "no decrypt"

View solution in original post

2 REPLIES 2

Cyber Elite
Cyber Elite

Hi @JarerkZajac ,

You can create Decryption rule, matching by destination address and using FQDN object with action set to "no decrypt"

Hi Astardzhiev,

thank you for answer and apologise for late reply. I solved this problem by adding FQDN to URL custom category and using it in decryption rule as no decrypt url category.

Chat.signal works fine, but lately another: signal messenger started the same -> no SNI, no SCN (subject common name), at the same IP/FQDN address. So I added new decrypt rule and added this address.

 

Thank you again for reply and solution.

 

Best

 

Jarek

 

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