Ublock: WebRTC local IP leakage prevention ineffective (Firefox 51)

[pfofi]

Describe the issue

Since Firefox 51 the privacy option Prevent WebRTC from leaking local IP addresses does not prevent websites from reading LAN IP addresses.

One or more specific URLs where the issue occurs

https://browserleaks.com/webrtc

Screenshot in which the issue can be seen

Browserleaks.com

Settings

Steps for anyone to reproduce the issue

1. Activate Prevent WebRTC from leaking local IP addresses in uBlock's settings menu
2. Go to https://browserleaks.com/webrtc
3. Look at the Local IP Address row

Your settings

• Browser/version: Firefox 51.0
• uBlock Origin version: 1.10.4
• OS: Windows 7 SP1 x64

(Also tested with Firefox 54.0a1 and uBlock 1.10.5rc1 - same issue.)

Possible solution

There is a new preference in Firefox 51 called media.peerconnection.ice.no_host. If it is set to true, local IPs don't seem to be leaking. https://wiki.mozilla.org/Media/WebRTC/Privacy

[ialexsilva]

Same settings where and same issue

Your settings

• Browser/version: Google Chrome 55.0.2883.87 m (64-bit)
• uBlock Origin version: 1.10.4
• OS: Windows 10 x64

[gorhill]

I don't have FF 51 yet, but I could reproduce with Nightly.

[gorhill]

Browser/version: Google Chrome 55.0.2883.87 m (64-bit)

Unable to reproduce with Chrome. Please open a detailed separate issue if you make the case there is one. Note that this is about "Local IP Address" here. Also, be sure no other extension is preventing uBO from controlling the setting in chrome://settings.

[ialexsilva]

Note that this is about "Local IP Address"

I forgot to look at this point 🤣