AT&T Hotspots: Now with Advertising Injection

While traveling through Dulles Airport last week, I noticed an Internet oddity. The nearby AT&T hotspot was fairly fast—that was a pleasant surprise.

But the web had sprouted ads. Lots of them, in places they didn’t belong.

Last I checked, Stanford doesn’t hawk fashion accessories or telecom service.1 And it definitely doesn’t run obnoxious ads that compel you to wait.

Exploring a Hacker Marketplace

In the sharing economy, you can hire a one-off driver (Uber), courier (Postmates), grocery shopper (Instacart), housekeeper (Homejoy), or just about any other variety of henchman (TaskRabbit). So, what about hiring a hacker?

That’s the premise of Hacker’s List, a website launched in November. Anyone can post or bid on a hacking project. Hacker’s List arranges secure communication and payment escrow.

An online black market is, to be sure, nothing new. The rise and fall of the Silk Road received extensive media coverage.

What’s unusual about Hacker’s List is that it, purportedly, isn’t a black market. The website is public, projects and bids are open (albeit pseudonymous), and the owner has identified himself. (He runs a small security firm in Denver.) Hacker’s List was even featured on the front page of the New York Times.

Out of curiosity, I decided to leverage this openness. Who tries to hire a hacker? Is the website as popular as its owner claims? Most importantly, does the website facilitate illegal transactions, or solely white hat hacking?

To answer these questions—and, admittedly, to procrastinate on my dissertation—I cobbled together a crawler. You can find the source on GitHub, and the crawl data on Google Docs.

Here’s the short version: most requests are unsophisticated and unlawful, very few deals are actually struck, and most completed projects appear to be criminal.

The Turn-Verizon Zombie Cookie

Verizon Wireless injects a unique header into customer web traffic. When the practice came to light last year, it was widely panned. Numerous security researchers pointed out that this “supercookie” could trivially be used to track mobile subscribers, even if they had opted out, cleared their cookies, or entered private browsing mode.1 But Verizon persisted, emphasizing that its own business model did not use the header for tracking.

Out of curiosity, I went looking for a company that was taking advantage of the Verizon header to track consumers. I found one—Turn, a headline Verizon advertising partner. They’re “bringing sexy back to measurement.”


MetaPhone: The Sensitivity of Telephone Metadata

Co-authored by Patrick Mutchler.

Is telephone metadata sensitive? The debate has taken on new urgency since last summer’s NSA revelations; all three branches of the federal government are now considering curbs on access. Consumer privacy concerns are also salient, as the FCC assesses telecom data sharing practices.

President Obama has emphasized that the NSA is “not looking at content.” “[T]his is just metadata,” Senator Feinstein told reporters. In dismissing the ACLU’s legal challenge, Judge Pauley shrugged off possible sensitive inferences as a “parade of horribles.”

On the other side, a number of computer scientists have expressed concern over the privacy risks posed by metadata. Ed Felten gave a particularly detailed explanation in a declaration for the ACLU: “Telephony metadata can be extremely revealing,” he wrote, “both at the level of individual calls and, especially, in the aggregate.” Holding the NSA’s program likely unconstitutional, Judge Leon credited this view and noted that “metadata from each person’s phone ‘reflects a wealth of detail about her familial, political, professional, religious, and sexual associations.’”

This is, at base, a factual dispute. Is it easy to draw sensitive inferences from phone metadata? How often do people conduct sensitive matters by phone, in a manner reflected by metadata?

MetaPhone: The NSA’s Got Your Number

Co-authored with Patrick Mutchler.

MetaPhone is a crowdsourced study of phone metadata. If you own an Android smartphone, please consider participating. In earlier posts, we reported how automated analysis of call and text activity can reveal private relationships, as well as how phone subscribers are closely interconnected.

“You have my telephone number connecting with your telephone number,” explained President Obama in a PBS interview. “[T]here are no names . . . in that database.”

Versions of this argument have appeared frequently in debates over the NSA’s domestic phone metadata program. The factual premise is that the NSA only compels disclosure of numbers, not names. One might conclude, then, that there isn’t much cause for privacy concern.

MetaPhone: Seeing Someone?

Co-authored with Patrick Mutchler.

Two weeks ago we kicked off the MetaPhone project, a crowdsourced study of phone metadata. Our aim is to inform policy and legal debates surrounding dragnet surveillance programs. We are exceedingly grateful to the hundreds of users who have joined. If you have not yet participated, you can still grab the MetaPhone app for Android.

Today we are excited to share some preliminary results: We can predict many romantic relationships. Automatically. Using solely phone metadata.

What’s In Your Metadata?

Original at Stanford CIS.

Co-authored with Patrick Mutchler. This is a project of the Stanford Security Lab.

We’re studying the National Security Agency, and we need your help.

The NSA has confirmed that it collects American phone records. Defenders of the program insist it has little privacy impact and is “not surveillance.”

Like many computer scientists, we strongly disagree. Phone metadata is inherently revealing. We want to rigorously prove it—for the public, for Congress, and for the courts.

That’s where you come in. We’re crowdsourcing the data for our study. We’ll measure how much of your Facebook information can be inferred from your phone records.

Participation takes just a few minutes. You’re eligible if you’re in the United States, use an Android smartphone, and have a Facebook account.

To get started, grab the MetaPhone app from Google Play.

The Web Is Flat

Consider this a bug report for the National Security Agency and its overseers. Dragnet online surveillance may be directed at international activity. But it nonetheless ensnares ordinary Americans as they browse domestic websites.

The spy outfit admits to vacuuming vast quantities of network traffic as it passes through the United States. Some taps are on the nation’s borders; others are on the domestic Internet backbone. International partner agencies, most prominently the UK’s Government Communications Headquarters, contribute to the NSA’s reach. Recent leaks have provided substantial detail: Under the Marina program, the agency appears to retain web browsing activity for a year.1 The XKeyscore system offers at least one way for analysts at the NSA and cooperating services to efficiently query both historical and realtime data.

Agency apologists are quick to point out that the snooping has limits. The NSA only acquires online communications when a sender or recipient seems international. Doing otherwise might, in their view, violate congressional restrictions or constitutional protections.

Tough luck for foreigners. But if you’re within the United States, the notion goes, you don’t have much cause for concern.

That’s wrong. Americans routinely send personal data outside the country. They just might not know it.