Vulnerabilities in billions of Wi-Fi devices let hackers bypass firewalls

One of the things that makes Wi-Fi work is its ability to break big chunks of data into smaller chunks and combine smaller chunks into bigger chunks, depending on the needs of the network at any given moment. These mundane network plumbing features, it turns out, have been harboring vulnerabilities that can be exploited to send users to malicious websites or exploit or tamper with network-connected devices, newly published research shows.

In all, researcher Mathy Vanhoef found a dozen vulnerabilities, either in the Wi-Fi specification or in the way the specification has been implemented in huge numbers of devices. Vanhoef has dubbed the vulnerabilities FragAttacks, short for fragmentation and aggregation attacks, because they all involve frame fragmentation or frame aggregation. Broadly speaking, they allow people within radio range to inject frames of their choice into networks protected by WPA-based encryption.

“It's never good to have someone able to drop packets into your network or target your devices on the network,” Mike Kershaw, a Wi-Fi security expert and developer of the open source Kismet wireless sniffer and IDS, wrote in an email. “In some regards, these are no worse than using an unencrypted access point at a coffee shop—someone can do the same to you there, trivially—but because they can happen on networks you'd otherwise think are secure and might have configured as a trusted network, it's certainly bad news.”

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