Information disclosure-Referer leak

Assigned to: Brave Assigned by: Kirtikumar Anandrao Ramchandani Assigned on: 13/09/2021 Browser information used to test (Up to date): ``` Brave 1.29.79 Chromium: 93.0.4577.63 (Official Build) (64-bit) Revision ff5c0da2ec0adeaed5550e6c7e98417dac77d98a-refs/branch-heads/4577@{#1135} OS Windows 10 OS Version 2009 (Build 19043.1165) ``` Vulnerability name: Information Disclosure Vulnerability description: Brave browser has a function of `New Private Window with Tor`. The browser when used with Tor shouldn't leak the referer. Steps to reproduce: 1. Visit [exploit]. 2. Click on `https://www.whatismybrowser.com/`. Expected behavior: It should have shown a blank `referrer` Actual behavior: It shows the referrer as: `kirtikumarar.com` which was the host from where we navigated To know expected behavior, please refer to the below screenshot: {F1445735} Video POC showing the expected behavior can be found below: {F1445736} [exploit]: https://kirtikumarar.com/referrer/top-page.html ## Impact 1. This will leak users information 2. In the Tor network, we don't have common URLs as we have in the browsers. They usually are something like `dhxnafkaxlxdnackeudxdca.onion`, those can be leaked.