The messenger app WhatsApp comes with a feature that lets you know when someone is online or the last time that person was online. However it also seems that this particular feature could be used to stalk someone where you could potentially find out what they might be chatting with, and even their sleeping patterns.

This is according to a recent blog post by software engineer Rob Heaton in which he found that thanks to a vulnerability, WhatsApp could be used to spy on other people. According to Heaton, he imagines how someone could create a Chrome extension and use it to monitor the online status of your contacts on WhatsApp for web.

Based on this, not only could one infer from this data the sleeping patterns of someone, but it could also potentially be used to figure out who the other person might be talking to based on the online/offline status. Note that WhatsApp allows users to hide their last seen status, but regardless of whether that feature has been enabled/disabled, users will show “online” when they are online, and that’s what’s being used to track their activities.

It isn’t so much a security vulnerability, but Heaton suggests that this data could potentially be collected a third-party and sold to other companies for marketing purposes. Whether or not Facebook/WhatsApp plans to address this remains to be seen.

Filed in General. Read more about Apps, Hack, Privacy, Security, Social Hit, Whatsapp and _cold.

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