denial of service

3 Articles

Extra-Large Denial Of Service Attack Uses DVRs, Webcams

September 26, 2016 by 46 Comments

Brace yourselves. The rest of the media is going to be calling this an “IoT DDOS” and the hype will spin out of control. Hype aside, the facts on the ground make it look like an extremely large distributed denial-of-service attack (DDOS) was just carried out using mostly household appliances (145,607 of them!) rather than grandma’s old Win XP system running on Pentiums.

Slide from <a href="http://slideplayer.org/slide/906693/">this talk</a> by Lisa Plesiutschnig
Replace computers with DVRs. Slide from this talk by Lisa Plesiutschnig

We can argue all day about whether a digital video recorder (DVR) or an IP webcam is an “IoT” device and whether this DDOS attack is the biggest to date or merely among them, but the class of devices exploited certainly are not traditional computers, and this is a big hit. Most of these devices run firmware out of flash, and it’s up to the end user (who is not a sysadmin) to keep it up to date or face the wrath of hackers. And it’s certainly the case that as more Internet-facing devices get deployed, the hacker’s attack surface will grow.

Why did the DDOS network use these particular devices? We’re speculating, but we’d guess it’s a combination of difficult-to-update firmware and user “convenience” features like uPnP. To quote the FBI “The UPnP describes the process when a device remotely connects and communicates on a network automatically without authentication.” You can see how this would be good for both the non-tech-savvy and hostile attackers, right? (Turn off UPnP on your router now.)

We alternate between Jekyll and Hyde on the IoT. On one hand, we love having everything in our own home hooked up to our local WiFi network and running on Python scripts. On the other hand, connecting each and every device up to the broader Internet and keeping it secure would be a system administration headache. Average users want the convenience of the latter without having to pay the setup and know-how costs of the former. Right now, they’re left out in the cold. And their toasters are taking down ISPs.

Inject Packets With An ESP8266

January 14, 2016 by 35 Comments

[Kripthor] sent us a link to his blog where he writes the Hello World of low-level networking. Basically he’s constructing his own packet and sending it. By itself this isn’t a bad thing. You could use this power for all sorts of networks-diagnostic good. And so, despite the ominous name of his blog post “ESP8266 Jamming”, he’s not really doing anything that bad — he’s just creating many fake WiFi beacon frames and sending them out every so often.

Which can apparently do bad things to some vulnerable routers. Who knew? Want to test yours?

Naturally we wanted to see how he was doing it, and we opened up the Arduino code in GitHub. It turns out that Espressif has written a wifi_send_pkt_freedom() function that just sends out whatever packet you’d like to the network. That was easy.

It also turns out that the ESP8266 will enter monitor mode, where it listens to all WiFi traffic regardless of the MAC address that it’s directed toward. [Pulkin] seems to have done the work for us and posted the code in his GitHub. Now things get nasty. Combining promiscuous monitor mode with some carefully constructed management frames can end up with a classic WiFi deauth denial-of-service attack on a $2 piece of hardware.

We think it’s tremendously cool that the ESP8266 packs such power, and we beg you all to use it responsibly. The last thing we want to see is the world littered with WiFi-DOS throwies. And the last thing you’d want is a visit from the FCC.