How does Azure Bastion monitor the clipboard?

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jimk889-7596 asked Mar 19, '21 SaiKishor-MSFT answered Mar 23, '21

How does Azure Bastion monitor the clipboard?

Bastion sessions have this fantastic feature of keeping the clipboard synced between the remote machine and the accessing machine.

Based on the initial request to access the clipboard by the browser we receive when we open a Bastion session, I can tell that it uses the clipboard API, https://developer.mozilla.org/en-US/docs/Web/API/Clipboard_API.

But how does it achieve monitoring of the clipboard? Does it query the clipboard every x seconds to see if the contents have changed? It seems too fast for that to be the case here.

azure-bastion

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Answer 1 · 2021-03-20T00:45:12.54Z

SaiKishor-MSFT answered Mar 20, '21 jimk889-7596 commented Mar 22, '21

@jimk889-7596 Unfortunately this is internal information and cannot be shared. Please let us know if you have any other questions and we will be glad to answer. Thank you!

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jimk889-7596 · Mar 22, 2021 at 05:01 PM

Thank you, I completely understand that this can't be shared. Could you at least let me know if it is making repeated queries to the clipboard? Because I'm trying to figure out some problems my specific browser is having with bastion and I suspect it is partially related to this clipboard functionality. How does bastion know when the clipboard has changed is all I want to know, and I cannot think of any way other than checking it periodically.

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Answer 2 · 2021-03-23T18:03:04.113Z

SaiKishor-MSFT answered Mar 23, '21

@jimk889-7596

We are doing it via browser's 'cut' and 'copy' events. This is done via
https://developer.mozilla.org/en-US/docs/Web/API/Element/cut_event
https://developer.mozilla.org/en-US/docs/Web/API/Element/copy_event

Hope this helps. Let us know if you have anymore questions. Thank you!

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