I have disabled Web Assembly in my Chrome, but nothing changed

[detro]

Chrome Version 65.0.3325.181 (Official Build) (64-bit)

I then tried different WASM application, especially coinhive.com and other ads-crypto-miners: they all still work just fine.

I'm trying to protect myself without the need of using AdBlock for it. But Chrome is making it really hard.

[tophf]

This flag does not disable WebAssembly. You need to run Chrome with --js-flags=--noexpose_wasm command line flag. Look for tutorials on altering Chrome shortcut for your OS.

In Windows you might also want to modify the chrome's command line in registry: HKEY_CLASSES_ROOT\ChromeHTML\shell\open\command HKEY_CLASSES_ROOT\http\shell\open\command HKEY_CLASSES_ROOT\https\shell\open\command And then uncheck the write permission on these keys so that the changes persist on next auto-update of Chrome.

Note, many/all miners run a fallback code in pure js.

[eladkarako]

This flag does not disable WebAssembly. You need to run Chrome with --js-flags=--noexpose_wasm command line flag.

acording to Chromium's code ^{#1, #2}, both enable-asm-wasm & enable-wasm were not disabled but migrated to feature flag, this means that to disable wasm in Chrome based browsers one should pass --disable-features=WebAssembly,AsmJsToWebAssembly to the chrome execute as a command-line argument. I guess using --js-flags="..." will work too but I haven't tried it..

[stevespringett]

I tried --disable-features=WebAssembly,AsmJsToWebAssembly but it didn't work on Chrome 66 (macOS). --js-flags=--noexpose_wasm does work consistently for me though.

On macOS, we need to start Chrome using the following command:

open /Applications/Google\ Chrome.app --args --js-flags=--noexpose_wasm

It should be noted that the Brave browser (Laptop edition) is build on Chromium and Webassembly can be disabled by the same method, using --js-flags=--noexpose_wasm

[stevespringett]

@tophf thanks for the updates on chrome, specifically the command-line arg and the registry advise. I've added the content to the projects readme and acknowledged your contribution.

[detro]

I will give it another go, but I checked all of the above and even got a bug about this o the Mac OS X version of Chrome open and assigned: https://bugs.chromium.org/p/chromium/issues/detail?id=825845

If this is now working as expected, it means in the meantime they fixed it.

[eladkarako]

@stevespringett its good to know, I'm having them both anyway --disable-features="WebAssembly,AsmJsToWebAssembly,WebAssemblyStreaming" --js-flags="--noexpose-wasm".

_{..along with a chrome extension I've made that sets self.WebAssembly = undefined; before the pages loads-up, effectively erasing the API from existence from the page and every iframe in-it (you can do the same with APIs such as WebSocket, IndexedDB, History, etc...)}

those arguments are already being added to chrome://version/ when switching the suitable flags in Chromium's chrome://flags/#enable-asm-webassembly, so it might take a while until it will effect Google Chrome.

[stevespringett]

Ah, very good background information @eladkarako . Thank you. If you find that the flags make it into Google Chrome before I do, please ping this ticket and update it if you could.

[basketdou]

Hello. Version 91.0.4472.164 (Official Build) Arch Linux (64-bit) I managed to turn off WebAssembly by disabling the following parameters in chrome://flags:

• #enable-webassembly-baseline
• #enable-webassembly-lazy-compilation
• #enable-webassembly-simd
• #enable-webassembly-threads
• #enable-webassembly-tiering .

It seems that it is off now after launching this script from StackOverflow. Option --js-flags=--noexpose_wasm didn't work for some reason.