There is now a technique available that governments and Internet service providers could use to bypass secured Internet connections and gather valuable personal information.
The “analysis attack” on HTTPS traffic had an 89 percent accuracy rate in determining the Web pages a person visited, said researchers at the University of California, Berkeley. Such tracking made it possible for the researchers to gather information on medical conditions, sexual orientation, financial status and whether a person is involved in a divorce or bankruptcy proceeding.
The study looked at more than 463,000 page loads on 10 widely used, industry-leading websites. Healthcare sites included those of the Mayo Clinic, Planned Parenthood and Kaiser Permanente; financial sites belonged to Wells Fargo, Bank of America and Vanguard; legal services sites belonged to the American Civil Liberties Union and Legal Zoom; and video-streaming sites included Netflix and YouTube.
For the attack to work, snoops would have to be able to visit the same Web pages as the victim, which would enable the attackers to identify packet patterns in encrypted traffic that would be indicative of different Web pages, according to Brad Miller, co-author of the study.
The attackers must also be able to observe victim traffic, which would allow them to match those packet patterns with the ones going to particular Web pages.
Researchers also developed a defense that cut down the amount of packet information an attacker could gather. The technique lowered the accuracy of identifying Web pages visited by people from 89 percent to 27 percent.
This research has huge privacy implications:
• Being able to examine user activity on a healthcare site could reveal medical conditions, which could lead to discrimination or could end up sold to advertisers looking to pitch products.
• Monitoring legal site traffic could uncover a divorce, bankruptcy or immigration status
• Analyzing traffic on a banking site could show whether a person has children, is in a long-term relationship or is in a high-income bracket.
• Any company with access to HTTPS traffic, such as Internet service providers and commercial chains of Wi-Fi access points, could gather data on users despite the encryption and sell the information to advertisers, the study said.
• Employers could monitor the activities of employees while they are on the corporate network, regardless of whether they are using a personal or employer-issued device.
• Governments could find the collected information useful to find criminals and to punish political dissidents or people who defy censors.