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0 points5424585y ago0 comments

Wouldn’t that be impossible to do as you’d have to somehow execute every code path in the plugin? The domains don’t have to exist as strings - there are lots of ways to obfuscate network requests.

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13 comments · 3 top-level

ashtonkem5y ago· 4 in thread

I think you’re right if you’re trying to enumerate where a plug-in will call. However it’s also possible to require that a plug-in provide a list of domains it will call as part of its manifest, display that list to the user and use it as a white list for network access by the plug-in.

This ends up effect as magically determining where it’ll call, with a lot less work.

wlesieutre5y ago

Except the add on can inject js into webpages that you have open and let the page make connections outside the extension sandbox.

lukevp5y ago

Also it’s pretty easy to just proxy requests through a whitelisted server side site so https://good.com is all that shows but it requests good.com?dest=https://evil.com

2 more replies

Triv8885y ago

Is that why Mozilla is blocking all addons on mobile (except for the selected 11)? They need to fix that shit or start adding useful features to Firefox... Not sure why they arent blocking all extensions on desktop too if they are so bad though.

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ashtonkem5y ago

Ah, that’s clearly a big issue. Never mind.

gruez5y ago· 3 in thread

Depending on how you approach it you either end up having to solve the halting problem (spoiler: it's impossible), or restricting what domains an addon can connect to (also impossible given the way addons work. they can inject arbitrary scripts into pages to make requests for them).

paulryanrogers5y ago

It's possible to make extensions declare which hostnames or registrable domains they need to communicate with. (Apart from pages in which they can run which is already defined with WebExtensions.)

Triv8885y ago

But you have all the code and you know which functions/methods/etc that can do requests so it should be trivial... either way, if it is not a solvable problem, there is a major problem in the design.

gruez5y ago

>But you have all the code and you know which functions/methods/etc that can do requests so it should be trivial

but you can't. See the last part of my comment: "they can inject arbitrary scripts into pages to make requests for them".

>either way, if it is not a solvable problem, there is a major problem in the design.

Not really. It's like complaining that debuggers can impersonate programs they attach themselves to.

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fiddlerwoaroof5y ago· 3 in thread

If you enumerate the ways browsers can make network requests, and if you have access to the source code of the extension, you could prepend the code with a bit of JavaScript that replaces the various network-related functions and methods with code that logs and/or validates the URL before making a request.

whoopdedo5y ago

The attacker will then inspect itself to see if network loggers are being used, or if it's running in a test environment (network location, machine fingerprint, et.al.) then adapt its behavior accordingly to avoid setting off any warnings.

fiddlerwoaroof5y ago

No, I’m saying modify the source of the extension so that the extension can only make requests to a whitelist of urls. The extension might be able to disable malicious functionality or something, but you can be certain that it’s not making malicious requests.

prox5y ago

On my android tablet they checked if my keyboard was us/eu (rain down the malware) or russian/chinese (Keep the app as-is)

And this was Google Play verified with a million downloads.

j / k navigate · click thread line to collapse

0 comments

13 comments · 3 top-level

ashtonkem5y ago· 4 in thread

This ends up effect as magically determining where it’ll call, with a lot less work.

wlesieutre5y ago

Except the add on can inject js into webpages that you have open and let the page make connections outside the extension sandbox.

lukevp5y ago

Also it’s pretty easy to just proxy requests through a whitelisted server side site so https://good.com is all that shows but it requests good.com?dest=https://evil.com

2 more replies

Triv8885y ago

1 more reply

ashtonkem5y ago

Ah, that’s clearly a big issue. Never mind.

gruez5y ago· 3 in thread

paulryanrogers5y ago

It's possible to make extensions declare which hostnames or registrable domains they need to communicate with. (Apart from pages in which they can run which is already defined with WebExtensions.)

Triv8885y ago

But you have all the code and you know which functions/methods/etc that can do requests so it should be trivial... either way, if it is not a solvable problem, there is a major problem in the design.

gruez5y ago

>But you have all the code and you know which functions/methods/etc that can do requests so it should be trivial

but you can't. See the last part of my comment: "they can inject arbitrary scripts into pages to make requests for them".

>either way, if it is not a solvable problem, there is a major problem in the design.

Not really. It's like complaining that debuggers can impersonate programs they attach themselves to.

1 more reply

fiddlerwoaroof5y ago· 3 in thread

whoopdedo5y ago

fiddlerwoaroof5y ago

prox5y ago

On my android tablet they checked if my keyboard was us/eu (rain down the malware) or russian/chinese (Keep the app as-is)

And this was Google Play verified with a million downloads.

j / k navigate · click thread line to collapse