Broken TLS certificate pinning in VTech DigiGo Kid Connect app

[Summer of Pwnage <lists () securify nl>]

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Broken TLS certificate pinning in VTech DigiGo Kid Connect app
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Sipke Mellema, September 2017

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Abstract
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VTech's DigiGo is a hand held smart device for children. The device
contains a chat application chatting with friends and family, called Kid
Connect. The app has a broken certificate pinning implementation that
allows a man in the middle attack on text sent by the chat app.

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Tested versions
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This issue was tested on a VTech DigiGo running firmware version
83.60630. It is likely that other versions are also affected.

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Fix
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VTech pushed a firmware update to address this issue on 6 November,
2017. The firmware version still displays as 83.60630.

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Details
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https://sumofpwn.nl/advisory/2017/broken-tls-certificate-pinning-in-vtech-digigo-kid-connect-app.html