Security researchers recently publicly disclosed a major vulnerability in the WPA2 encryption protocol. Most devices and routers currently rely on WPA2 to encrypt your WiFi traffic, so chances are you’re affected. But first, let’s clarify what an attacker can and cannot do using the KRACK vulnerability.

The attacker can intercept some of the traffic between your device and your router. If traffic is encrypted properly using HTTPS, an attacker can’t look at this traffic. Attackers can’t obtain your Wi-Fi password using this vulnerability. They can just look at your unencrypted traffic if they know what they’re doing. With some devices, attackers can also perform packet injection and do some nasty things. This vulnerability is like sharing the same WiFi network in a coffee shop or airport.
The attacker needs to be in within range of your WiFi network. They can’t attack you from miles and miles away. The attacker could also take control of a zombie computer near you, but this is already a much more sophisticated attack. That’s why companies should release patches as soon as possible because chances are most attackers just learned about this vulnerability today.

There’s at least a theoretical possibility that this vulnerability could be exploited by hackers to make it more scalable as an attack vector in future, for example, how worms have been developed and released that spread from one insecure IoT device to another to build a zombie botnet. But currently, this is not the case.
So here’s what to do now that the WPA2 protocol is vulnerable…

Update all the wireless things you own

Good news! Your devices can be updated to prevent the KRACK vulnerability. Updated devices and non-updated devices can co-exist on the same network as the fix is backward compatible.
So you should update all your routers and Wi-Fi devices (laptops, phones, tablets etc…) with the latest security firmware/patches. You should also consider turning on auto-updates for future vulnerabilities as this won’t be the last one. Modern operating systems have become quite good at auto-updates. Some devices (ahem Android) don’t receive a lot of updates and could continue to pose risks.
The main point is that both clients and routers need to be fixed against KRACK so there are lots of potential attack vectors to consider.

Look at your router

Your router’s firmware definitely needs to be updated. If the router has been supplied by your ISP, ask the company when their branded devices will be updated. If they don’t have an answer, keep asking. You can make sure your router is up-to-date by browsing the administration panel. Find the user guide for your ISP-branded router and follow the instructions to connect to the admin pages.
If your ISP is not quickly putting out a firmware update to fix KRACK, it may be time to consider switching your ISP. A less drastic option would be to buy a WiFi router from a responsible company that has already issued a patch. Plugging a WiFi router into your ISP router and disabling WiFi on your antique ISP hardware is a good alternative.
Here’s a list of some of the router makers that have already put out fixes (Ubiquiti, Microtik, Meraki, Aruba, FortiNet…).

Use Ethernet

If your router doesn’t yet have a fix, and you don’t have a patched WiFi access point that could be used for wireless instead, you could Ethernet into your router and turn off its wireless function until it’s updated (assuming WiFi can be disabled on your router). Turn off WiFi on your device as well so that you’re sure all traffic goes through the Ethernet cables.
If you still want to keep WiFi for some devices, consider switching to Ethernet for your essential devices. For instance, if you spend hours every day on a computer and use a ton of internet traffic from this computer, buy an Ethernet cable.

Consider using cellular data on your phone

Your phones and tablets don’t have an Ethernet port. If you want to make sure nobody is watching your traffic, disable WiFi on your device and use cellular data instead. This isn’t ideal if you live somewhere with a spotty network, pay extra for mobile data, or if you don’t trust your telecom provider.
Devices running Android 6.0 and later are more vulnerable than other devices. It is trivially easy to perform a key reinstallation attack because of a bad implementation of the handshake mechanism in the WiFi stack. So Android users do need to be more careful.

What about Internet-of-Things devices?

If you own a lot of IoT devices, consider which of those devices pose the most serious risk if unencrypted traffic were intercepted. Say, for example, you own a connected security camera that doesn’t encrypt traffic when you’re on the same WiFi network — well, that could allow attackers to snoop on raw video footage inside your home. Yikes!
Take action accordingly — e.g. by pulling the riskiest devices off your network until their makers issue firmware updates. And be sure to keep an eye on the kinds of devices your kids might be connecting to your home network.
At the same time, if an attacker can intercept traffic between your smart lightbulbs and your router, it’s probably fine. What are they going to do with this information anyway? It’s fair to say that Edward Snowden wouldn’t want even info about how his lightbulbs are being turned on and off getting into the hands of a hacker, and with good reason. But most people aren’t at risk of such an extreme level of state-sponsored surveillance. So you should determine your own level of risk and act accordingly.
That said, the Internet of Things does have a horrible reputation when it comes to security. So this could be a good moment to audit your connected device collection and consider junking any WiFi device whose makers don’t quickly issue a patch — they could pose some form of long term risk to your network.

Install the HTTPS Everywhere extension

As mentioned above, you can mitigate risks by prioritizing encrypted internet traffic over unencrypted traffic. The EFF has released a neat browser extension called HTTPS Everywhere. If you’re using Google Chrome, Firefox or Opera, you should consider installing the extension. There’s no need to configure it so that anybody can do it.
If a website offers unencrypted access (HTTP) and encrypted access (HTTPS), the extension automatically tells your browser to use the HTTPS version to encrypt your traffic. If a website still relies exclusively on HTTP, the extension can’t do anything about it. The extension is no use if a company has a poor implementation of HTTPS and your traffic isn’t really encrypted. But HTTPS Everywhere is better than nothing.

Don’t rely on a VPN as a solution

On paper, using a VPN server sounds smart. But we’ve been there already — be careful with VPN services out there. You can’t trust any of them.
When you use a VPN service, you reroute all your internet traffic to a VPN server in a data center somewhere. An attacker can’t see what you’re doing on your WiFi network, but a VPN company can log all your internet traffic and use it against you.
For instance, The Register discovered last week in a legal document that PureVPN shared key information with authorities to track and arrest a man. And yet, the company’s website claims that PureVPN doesn’t keep any log. Again, don’t trust any VPN company. Unless you’re willing to build your own VPN server, a VPN service is not the solution.

Especially paranoid? Move to the woods…
For the most paranoid out there, who don’t want to/can’t stop using WiFi entirely, it may be time to relocate to a remote cabin in the woods far from any neighbors.