An exploitable vulnerability exists in the firmware update functionality of Circle with Disney. Specially crafted network packets can cause the product to run an attacker-supplied shell script. An attacker can intercept and alter network traffic to trigger this vulnerability.
Circle with Disney
9.6 - CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CWE-300: Channel Accessible by Non-Endpoint (‘Man-in-the-Middle’)
Circle with Disney is a network device used to monitor and restrict internet use of children on a given network. When connected to a given network and configured, it immediately begins ARP poisoning all other devices on the network, such that it can validate and restrict all traffic as is seen fit by the parent/administrator of the device.
Periodically, the device will query outbound towards the meetcircle.co domain, checking to see if there is a firmware update available. Upon detection of a new version, the server will grab the newest firmware_updater.sh script and run it. Unfortunately, both the version detection and the firmware_updater.sh script are acquired via a ‘wget’ over regular HTTP, such that it is possible to intercept and upload an arbitrary script to the device to be run as root. ARP poisoning is one of the easiest vectors to execute this attack with.
2017-07-13 - Vendor Disclosure
2017-10-31 - Public Release
Discovered by Lilith Wyatt <(^_^)>, Cory Duplantis, Yves Younan, Marcin 'Icewall' Noga, Claudio Bozzato, Aleksandar Nikolic, and Richard Johnson of Cisco Talos.