Dropbox Signature Change?

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Dropbox Signature Change?

L4 Transporter


We have for some time now blocked the use of Dropbox (as an app) and only allow a few users access, based on a domain group.  Over last couple of weeks have noticed activity where non allowed users are able to access the application. In my initial investigation, it appears the sessions are not falling into the "dropbox" application object - but rather straight "SSL".  Still investigating.  I have placed a request with App Research Center to verify if DropBox changed their signatures.  Curious if anyone has seen this also or if known by support.  Thanks!



L4 Transporter


As Dropbox uses a proprietary protocol for its file transfers, the signature is dynamic and can change over time.  If the content and threat detection engine is unable to match the specific signature that we have in our database for dropbox, it will fall back and identify it as SSL.  If you wish to submit the application to have a new signature generated, please do so using the following link:

< http://www.paloaltonetworks.com/researchcenter/submit-an-application/ >

It appears that you may have already submitted the request in the correct location.  You can check the release notes for each content update to see if dropbox signatures have been updated.


Thank you Graham!

That is a great explanation - appreciate it.  Now I have a better explanation to tell our compliance folks.  I did place a request to have it looked at.  Didn't make it in this week's content update - but will watch for it in a future update.



Forgot to ask.  If we were running the SSL decryption - would that provide a sort of failover back to straight SSL - for the application object blocking? Or is the application objects independent of decryption? Thanks!

Due to the nature of Dropbox or possibly the company cert, it has been listed as an app excluded from ssl decryption.


I believe this signature needs updated.   The current version of Dropbox failes to "establish secure connection" when decription is enabled, regardless of the fact that Palo Alto has an exclusion.     4.1.7, with all of the latest dynamic software signatures installed.

I believe this might be because Dropbox is making use of the Amazon S3 network, which may have a different SSL certificate.  I am not certain that this is the issue, but it looks likely.

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