Contact-Tracing Apps Still Expose Users to Security, Privacy Issues

Current contact-tracing apps that do not use the Apple-Google Exposure Notifications protocol have failed to implement enough strong security measures, putting sensitive user data at risk, according to an updated survey of the applications conducted by mobile security firm Guardsquare.

The company analyzed 95 contact-tracing apps — 52 Android apps and 43 iOS apps — and found that 40% did not use the Apple-Google protocol, which is designed to protect user privacy. Many of those applications instead used global positioning system (GPS) data to determine users' locations and linked that to their phone numbers or passport identifiers, the company stated in the analysis, published today.

Guardsquare did not want to "name and shame" companies and nations that took the home-brew approach, but linking GPS location with identifying details turns a helpful healthcare application into a method of surveillance, says Grant Goodes, chief scientist at Guardsquare.

"As a mobile phone user, I generally only turn on my location information for mapping apps. I don't allow other apps, like shopping apps, know where I am," he says. "If you combine GPS data and a passport number and send it to a server in an insecure manner, then I'm very concerned."

While contact tracing has waned in importance as nations have either kept the pandemic under control or succumbed to pandemic fatigue and experienced spikes in infections, such applications could prove critical for future outbreaks. Appropriately securing the applications and guaranteeing certain levels of privacy will be key in convincing users to install the applications. 

In June, Guardsquare surveyed 17 Android apps and found only one that fully encrypted and obfuscated data.

In the latest survey of contact-tracing apps, the company examined 95 apps and found that 32 Android apps and 25 iOS apps used the official API of the Exposure Notifications system created by Apple and Google. Because the companies designed the API to protect privacy, user data is never exposed and so the apps are considered secure, Goodes says.

Yet, of the 40% that did not use the official Exposure Notifications, only about 5% used more than two out of six necessary security measures, including encrypting sensitive strings, encrypting data at rest, linking hosts to their SSL keys, and monitoring the device for a jailbreak. 

"Unfortunately, though more apps have been rolled out since June, and though the Google/Apple API has made a big dent in privacy and security concerns, many apps still do not properly safeguard user data," the report states.

Creating a strongly pro-privacy platform is critical to convincing users to adopt the technology. 

In April, Apple and Google announced they would work together on a way to detect exposure to people with COVID-19 using the capabilities of mobile devices and the Bluetooth communications protocol. The Exposure Notifications protocol assigns a device a key that changes every 10 to 20 minutes, stores the keys locally, and only transmits the last 14 days of keys if the device's owner is diagnosed with COVID-19 and gives their permission, according to an FAQ published by the companies.

The two companies made privacy the paramount concern, requiring users to turn on the technology explicitly, preventing the device from sending the keys to others, and randomizing and rotating the keys so they anonymize the user. Every day, users' devices will download the list of keys for infected mobile users and, if a key matches, will be notified they have been exposed.

Apple and Google's approach is the gold standard and is widely used in North America and Europe, Goodes says. While he would not name the specific apps that used GPS technology or a custom Bluetooth protocol for detecting proximity, Goodes did say that many of the countries that deployed the apps were less democratic with stronger central governments.

"Properly securing contact-tracing apps is not just a citizen privacy and security issue," the report stated. "It's not just a government trust issue. Most importantly, it's a public health concern."

Because the pressure for electronic contact tracing will likely fade as the coronavirus vaccine is deployed, technology companies and national governments have time to get the technology right for the next time it is needed. Governments need to make plans, including specifications that require privacy and security, Goodes says.

"I would have loved to have seen that there was a greater focus on security," he says. "The government authorities should have put into the [request for proposal] that security was a required thing."