A network router is a device which forwards traffic between two networks. Your computer is on one segment of the internet, and your favorite web site is (likely) on a different segment. There’s at least one network router between you and your favorite web site moving the data packets back and forth.
Routers will typically more-or-less work right out of the box, but they generally need some configuration to do their jobs well (and securely). Routers frequently offer a web interface for this: you connect a computer to the router, go to a particular web address (specified by the product’s documentation), and then configure the device for its particular purpose. For example, if you’re setting up a router for an elementary school, you might configure the router to send all web traffic through some kind of content filter.
More and more devices are like this: you buy a shiny new gizmo, connect it to your network, and it offers some feature you can control with an app on your phone. This is the “Internet of Things” (IoT):
- monitor (and open or close) your garage door
- adjust the cooking temperature in the crock pot on your kitchen counter
- let the dog out (and back in) without even getting your ass off the couch
Network-enabled security cameras are another interesting example of this kind of thing. Imagine being able to log on to a camera hundreds of miles away, have it take pictures on demand, and view the images.
These devices typically ship with a default password. And that’s the big problem with these things: they don’t necessarily force you to change the password, and those default passwords are well documented and widely available: they’re in the product documentation that the manufacturer probably puts on their web site for anyone to download.
(Sometimes the manufacturer will try to assign a unique default password to every unit they sell. This is great when they do it right, but sometimes the fail hilariously.)
Shodan and Censys are projects which portscan the internet and make the data available to anyone who wants to look at it. This data often reveals the manufacturer and model number of internet routers. Netgear devices often give the full model number in the remote administration password prompt. And there are web sites (like routerpasswords.com) devoted to making it easy to look up the default password for a particular network device model.
There are two important points to remember here:
- If you are writing about a character who wants to compromise a network target, and if she can determine the manufacturer and/or model number of the router protecting her target (either through shodan or by portscanning it herself), she can look up the default password either through something like routerpasswords.com or by downloading product documentation from the manufacturer. If the network pukes at the target haven’t secured their router, your character could add routing table rules allowing her direct access to resources on the internal network.
- If you haven’t changed the password on the home router that may be sitting on your desk, now would be a good time to do so. (And unless you REALLY need it, you should disable the remote administration feature which was probably enabled by default.)