September 23, 2018

Website operators are in the dark about privacy violations by third-party scripts

by Steven Englehardt, Gunes Acar, and Arvind Narayanan.

Recently we revealed that “session replay” scripts on websites record everything you do, like someone looking over your shoulder, and send it to third-party servers. This en-masse data exfiltration inevitably scoops up sensitive, personal information — in real time, as you type it. We released the data behind our findings, including a list of 8,000 sites on which we observed session-replay scripts recording user data.

As one case study of these 8,000 sites, we found health conditions and prescription data being exfiltrated from walgreens.com. These are considered Protected Health Information under HIPAA. The number of affected sites is immense; contacting all of them and quantifying the severity of the privacy problems is beyond our means. We encourage you to check out our data release and hold your favorite websites accountable.

Student data exfiltration on Gradescope

As one example, a pair of researchers at UC San Diego read our study and then noticed that Gradescope, a website they used for grading assignments, embeds FullStory, one of the session replay scripts we analyzed. We investigated, and sure enough, we found that student names and emails, student grades, and instructor comments on students were being sent to FullStory’s servers. This is considered Student Data under FERPA (US educational privacy law). Ironically, Princeton’s own Information Security course was also affected. We notified Gradescope of our findings, and they removed FullStory from their website within a few hours.
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How the Contextual Integrity Framework Helps Explain Children’s Understanding of Privacy and Security Online

This post discusses a new paper that will be presented at the 2018 ACM Conference on Computer Supported Cooperative Work and Social Computing (CSCW). I wrote this paper with co-authors Shalmali Naik, Utkarsha Devkar, Marshini Chetty, Tammy Clegg, and Jessica Vitak.

Watching YouTube during breakfast. Playing Animal Jam after school. Asking Google about snakes. Checking points on Class Dojo. Posting a lip-synching video on Musical.ly. These online activities are interspersed in the daily lives of today’s children. They also involve logging into an account, disclosing information, or exchanging messages with others—actions that can raise privacy and security concerns.

How do elementary school-age children conceptualize privacy and security online? What strategies do they and their parents use to help address such concerns? In interviews with 18 families, we found that children ages 5-11 understand some aspects of how privacy and security apply to online activities. And while children look to their parents for support, parents feel that privacy and security are largely a concern for the future, when their children are older, have their own smartphones, and spend more time on activities like social media. (For a summary of the paper, see this Princeton HCI post.)

Privacy scholar Helen Nissenbaum’s contextual integrity framework was developed to help identify what privacy concerns emerge through the use of new technology and what types of solutions can address those concerns. We found that the framework is also useful to explain what children know (and don’t know) about privacy online and what types of educational materials can enhance that knowledge.

What is contextual integrity? The contextual integrity framework considers privacy from the perspective of how information flows. People expect information to flow in a certain way in a given situation. When it does not, privacy concerns may arise. For example, the norms of a parent-teacher conference dictate that a teacher can reveal information about the parent’s child to the parent, but not about other children. Four parameters influence these norms:

  • Context: This relates to the backdrop against which a given situation occurs.  A parent-teacher conference occurs within an educational context.
  • Attributes: This refers to the types of information involved in a particular context. The parent-teacher conference involves information about a child’s academic performance and behavioral patterns, but not necessarily the child’s medical history.
  • Actors: This concerns the parties involved in a given situation. In a parent-teacher conference, the teacher (sender) discloses information about the student (subject) to the parent (recipient).
  • Transmission Principles: This involves constraints that affect the flow of information. For example, information shared during a parent-teacher conference is unidirectional (i.e. teachers don’t share information about their own children with parents) and confidential (i.e. social norms and legal restrictions prevent teachers from sharing such information with the entire school).

How does the contextual integrity framework help us understand what children know about privacy and security online? In our interviews, we found that children largely understood how attributes and actors could affect privacy and security online. They knew that certain types of information, such as a password, deserved more protection than others. They also recognized that it was more appropriate to share information with known parties, such as parents and teachers, rather than strangers or unknown people online.

But children under age 10 struggled to grasp how interacting online could violate transmission principles by, for example, enabling unintended actors to see information. Only one child recognized that someone could take information shared in a chat message and repost it elsewhere, potentially spreading it far beyond its intended audience. Children also struggled to understand how the context of a situation could inform decisions about how to appropriately share information. They largely used the heuristic of “Could I get in trouble for this?” to guide behavior.

How do children and parents navigate privacy and security online? While a few children understood that restricting access to information or providing false information online could help them protect their privacy, most relied on their parents for support in navigating potentially concerning situations. Parents primarily used passive strategies to manage their children’s technology use. They maintained a general awareness of what their children were doing, primarily by telling children to use devices only when parents were around. They minimized the chances that their children would download additional apps or spend money by withholding the passwords for app stores.

Most parents felt their children were too young to face privacy or security risks online. But elementary school-age children already engage in a variety of activities online, and our results show they can absorb lessons related to privacy and security. Childrens’ willingness to rely on parents suggests that parents have an opportunity to usher their children’s knowledge to the next level. And parents may have an easier time doing so before their children reach adolescence and lose interest in listening to parents.

How can the contextual integrity framework inform children’s learning about privacy and security online? The contextual integrity framework can guide the development of relevant materials that parents and others can use to scaffold their children’s learning. For example, the development of a child-friendly ad blocker could help show children that other actors, such as companies and trackers, can “see” what people do online. Videos or games that explain, in an age-appropriate manner, how the Internet works, can help children understand how the Internet can challenge transmission principles such as confidentiality. Integrating privacy and security-related lessons into apps and websites that children already use can help refine their understanding of how contexts and norms shape decisions to disclose information. For example, the website for the public broadcasting channel PBS Kids instructs children to avoid using personal information, such as their last name or address, in a username.

As the boundaries between offline and online life continue to fade, privacy and security knowledge remains critical for people of all ages. Theoretical frameworks like contextual integrity help us understand how to to evaluate and enhance that knowledge.

For more information, read the full paper.