OSX update and Decryption

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Highlighted
L4 Transporter

OSX update and Decryption

I've installed our Root CA cert in the "System" keychain, and have it marked as trusted.  I can successfully decrypt web traffic from a MAC running Mojave.  No problems there. 

 

The problem comes in when I try updating the OSX or even check for updates from the CLI.   

 

When I run "softwareupdate -l"  in terminal, In the logs on the firewall it appears to be coming through as web browsing app, and getting decrypted.  

 

I ran a packet capture, and it shows the client is resetting the connection after succesffuly going out to swscan.apple.com, which is not whitelisted for decryption exclusions.  Has anyone run into issues when trying to decrypt on OSX with a trusted root cert, while trying to update the operating system itself?

 

Guessing adding these domains to decryption exclusion is going to fix this?

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Accepted Solutions
Highlighted
Cyber Elite

@Sec101,

Whitelist the following:

  • gg.apple.com
  • gnf-mdn.apple.com
  • gnf-mr.apple.com
  • gs.apple.com
  • ig.apple.com
  • mesu.apple.com
  • skl.apple.com
  • swcdn.apple.com
  • swdist.apple.com
  • swdownload.apple.com
  • swpost.apple.com
  • swscan.apple.com
  • updates-http.cdn-apple.com
  • updates.cdn-apple.com
  • xp.apple.com

That should take care of the software updates and allow your clients to actually update successfully. 

View solution in original post

Highlighted
Cyber Elite

Correct. Exclude those domains from decryption and your clients should be able to check for and download updates again. 

View solution in original post


All Replies
Highlighted
Cyber Elite

@Sec101,

Whitelist the following:

  • gg.apple.com
  • gnf-mdn.apple.com
  • gnf-mr.apple.com
  • gs.apple.com
  • ig.apple.com
  • mesu.apple.com
  • skl.apple.com
  • swcdn.apple.com
  • swdist.apple.com
  • swdownload.apple.com
  • swpost.apple.com
  • swscan.apple.com
  • updates-http.cdn-apple.com
  • updates.cdn-apple.com
  • xp.apple.com

That should take care of the software updates and allow your clients to actually update successfully. 

View solution in original post

Highlighted
L4 Transporter

Perfect!  As always, an excellent reply!  Thank you.  When you say whitelist- you mean exclude decryption right?

Highlighted
Cyber Elite

Correct. Exclude those domains from decryption and your clients should be able to check for and download updates again. 

View solution in original post

Highlighted
L2 Linker

Hi,BPry

 

>Whitelist the following:

>....

 
Is this list actual?
 
 
 
 You mean path "Device -> Cert mgmt -> SSL Decription Exclusion" and add  all listed domains one by one?
Or "Policies -> Decryption -> New rule" and add rule with custom URL category.

 

Andrew

Highlighted
Cyber Elite

@aaobuhov,

That is the actual list yes. You can exclude these domains in either method, personally I like doing it in the decryption rulebase via a custom No-Decrypt URL category. 

Highlighted
L2 Linker

Thank you for reply 

I prefer "No-Decrypt URL category" too.

Can i summarize your list to:

*.apple.com

*.cdn-apple.com

 

It will be a less strict list.
Is such version possible?

 

Andrew

Highlighted
Cyber Elite

@aaobuhov,

You could. As you said, it would be less restrictive and potentially allow additional traffic that you otherwise could have decrypted and gained insight into. 

Highlighted
L2 Linker

Thank you, I understand.

 

Best wishes,
Andrew

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