How to block a certian chrome extension

[Peter_Bjeldbak]

Hi

Via URL filtering blade I often control access to certain sites / catagories.

Exams are up (at least in public schools in Denmark) and I would like to block a certain chrome extension - namely this

https://chrome.google.com/webstore/detail/txtanalyser/aaengkeeajpfabihmmmnkjpogmfkahjo

This extension offers the handy option to have a text checked for errors - not only spelling, but grammar and such - which is tempting understandable.

How would you go about doing this ?  

I cannot block dst adress or protocols - and since it all takes place within chrome - i feel i lack the ability to sort out this specific traffic. I cannot block extensions all together

Kind regards

Peter

[G_W_Albrecht]

Why not block chrome extensions at all for use at school ? Best for exams is to use prepared VMs for each pupil so all have the same standard environment.

[Peter_Bjeldbak]

Unfortunatly - certain extensions are "legal" and thus need to be accessible and hence i can not use this suggestion.

[G_W_Albrecht]

I would understand if extensions are necessary to the learning process, but legal is no argument ! Also using a Google Browser gives away so much personal information to Google that German or Austrian schools will stay with Firefox...

[_Val_]

I would assume the extension, like many others, use a cloud backend for text analysis and suggestions. You could try to back-engineer what those URLs are, by installing a sterile machine with this extension in the lab, and then sniffing DNS and HTTPS traffic. You also need HTTPSi active in this environment. I would assume the domains, DNS names and URLs would be in wizkids.dk subdomain, but that is not guaranteed. 

You can also reach out to the vendor and explicitly ask for that info. I would say something like

- "Our students complain about your extension not working well from time to time. Could you please help us to unblock all your traffic on our FWs? Can you please give us some details on how your backend is working?"

I assume the devices are not owned by the school, right? Otherwise, it is an option to lock Chrome and manage extensions centrally for the students.

 

[PhoneBoy]

For centrally managed computers, Chrome has the ability to restrict and centrally control what extensions can be loaded on a given installation.
See: https://support.google.com/chrome/a/answer/9296680?hl=en

For computers that are not centrally managed, there's probably not a lot you can do short of determining what traffic is being generated by this extension and blocking it.