Advertisers could be tracking you via your battery status

Graham Cluley

Advertisers could be tracking you via your battery status

Advertisers could be tracking you via your battery status

A legitimate reason to poll your battery’s status is to stop intensive operations from executing if you’re running low on juice.

But it’s also open to exploitation by those who want to track your online activity, writes Lukasz Olejnik:

The information provided by the Battery Status API is not always changing fast. In other words, they are static for a period of time; it may give rise to a short-lived identifier. At the same time, users sometimes clear standard web identifiers (such as cookies). But a web script could analyze identifiers provided by Battery Status API, which could then possibly even lead to recreation of other identifiers. A simple sketch follows.

An example web script continuously monitors the status of identifiers and the information obtained from Battery API. At some point, the user clears (e.g.) all the identifying cookies. The monitoring web script suddenly sees a new user – with no cookie – so it sets new ones. But battery level analysis could provide hints that this new user is – in fact – not a new user, but the previously known one. The script’s operator could then conclude and reason that those this is a single user, and resume with tracking. This is an example scenario of identifier recreation, also known as respawning.

A recent study reported that battery status is being monitored by some tracking scripts.

It sounds like it would be a positive step if browsers stopped accessing such detailed information about our battery.

Aside from tracking, there are other ways that battery information could be exploited.

Uber, for instance, says that it knows customers are more likely to accept a much higher price to hire a cab when their battery is running low.

Graham Cluley Graham Cluley is a veteran of the anti-virus industry having worked for a number of security companies since the early 1990s when he wrote the first ever version of Dr Solomon's Anti-Virus Toolkit for Windows. Now an independent security analyst, he regularly makes media appearances and is an international public speaker on the topic of computer security, hackers, and online privacy. Follow him on Twitter at @gcluley, or drop him an email.

One Reply to “Advertisers could be tracking you via your battery status”

  1. When Uber wants more money, I switch to Lyft! And they likely know I have both apps. Since I downloaded the competition, I've not seen a surge pricing yet. As for trackers in general, almost every adblocking add-on has the ability to block all tracking, plus I do use Self Destructing Cookies. Which means cookies are deleted just after not needed for every website I visited.

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