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.”
When the National Security Agency collects data inside the United States, it’s regulated by the Foreign Intelligence Surveillance Act. There’s a degree of court supervision and congressional oversight.
When the agency collects data outside the United States, it’s regulated by Executive Order 12333. That document embodies the President’s inherent Article II authority to conduct foreign intelligence. There’s no court involvement, and there’s scant legislative scrutiny.
So, that’s the conventional wisdom. American soil: FISA. Foreign soil: EO 12333. Unfortunately, the legal landscape is more complicated.
In this post, I’ll sketch three areas where the NSA collects data inside the United States, but under Executive Order 12333. I’ll also note two areas where the NSA collects data outside the United States, but under FISA.
In the debates surrounding intelligence reform, many observers have made a critical assumption. If Congress doesn’t act by mid-2015, it goes, the NSA’s controversial phone metadata program will turn into a pumpkin. In this post, I’m going to sketch why that view is so common—and why, regrettably, the clock may not strike midnight.
Over the past couple of days, there’s been an outpouring of concern about Verizon’s advertising practices. Verizon Wireless is injecting a unique identifier into web requests, as data transits the network. On my phone, for example, here’s the extra HTTP header.1
After poring over Verizon’s related patents and marketing materials, here’s my rough understanding of how the header works.
I’m excited to be teaching Stanford Law’s first Coursera offering this fall, on government surveillance. In preparation, I’ve been extensively poking around the platform; while I found some snazzy features, I also stumbled across a few security and privacy issues.
- Any teacher can dump the entire user database, including over nine million names and email addresses.
- If you are logged into your Coursera account, any website that you visit can list your course enrollments.
- Coursera’s privacy-protecting user IDs don’t do much privacy protecting.
The balance of this piece provides some detail on each of the vulnerabilities.
Update 9/4: Coursera has acknowledged the issues, and claims they are “fully addressed.” The second vulnerability, however, still exists.
Update 9/6: Coursera appears to have imposed rate limiting on the APIs associated with the second vulnerability, mitigating the risk to users. A malicious website can now iterate over about 10% of the course catalog before having to wait.
Retail analytics is a fraught field. The premise is straightforward: enable brick-and-mortar stores to track their customers. The technology is straightforward, too: monitor broadcasts from shoppers’ smartphones. Privacy concerns have, however, put a damper on the nascent industry. Regulators, legislators, and advocacy groups have questioned the legitimacy of surreptitiously monitoring shoppers’ gadgets.
Last fall, Senator Schumer announced a grand bargain with retail analytics firms. They will be bound by a “Mobile Location Analytics Code of Conduct,” a set of voluntary practices intended to assuage privacy fears. The document has already been widely panned, both as a product of backroom dealing, and for providing little substantive protection to consumers.
One particular point of contention is how the industry proposes to preserve privacy through cryptography. This post explains the Code of Conduct’s crypto, and demonstrates how it can trivially be undone.
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?
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.
Co-authored with Patrick Mutchler.
MetaPhone is a crowdsourced study of phone metadata. If you own an Android smartphone, please consider participating. In an earlier post, we reported how automated analysis of call and text activity can detect private relationships.
Does the National Security Agency have court authority to pore over your phone records? Quite possibly.
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.