Deep Web

Privacy bug in the Brave browser exposes Tor addresses to user’s DNS provider

A privacy bug in the Brave Browser caused the leak of the Tor onion URL addresses visited in the Tor mode by the users.

A bug in the Private Window with Tor implemented in the Brave web browser could reveal the onion sites visited by the users.

The Tor mode implemented in the Brave web browser allows users to access .onion sites inside Brave private browsing windows.

When users are inside a Private Window with Tor, Brave doesn’t connect directly to a website, instead, it connects to a chain of three different computers in the Tor network.

An anonymous researcher initially reported that the Brave’s Tor mode was sending queries for .onion domains to public internet DNS resolvers, other experts confirmed his findings.

“If you’re using Brave you probably use it because you expect a certain level of privacy/anonymity. Piping .onion requests through DNS where your ISP or DNS provider can see that you made a request for an .onion site defeats that purpose.” explained the researcher. “Anyhow, it was reported by a partner that Brave was leaking DNS requests for onion sites and I was able to confirm it at the time.”

Every query is saved in logs of the DNS server for the Tor traffic of Brave web browser users.

The Brave development team shortly after the public disclosure of the bug addressed it in The Brave Nightly version and it will be released to the stable version with the next Brave browser update.

According to the development team, the privacy bug resides in the internal ad blocker component of the Brave web browser. The component was using DNS queries to determine if a site was attempting to bypass the ad-blocking features, but the problem is that it performed the same checks for .onion addresses.

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Pierluigi Paganini

(SecurityAffairs – hacking, Brave web Browser)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.

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