Texas Instruments plans to patch a cryptography flaw in a widely used chip that could allow attackers to remotely tamper with electronic power meters and other devices that connect to smart electricity grids.
The weakness resides in TI's Z-Stack software that runs on microcontrollers such as the CC2430. Encryption keys used to protect and authenticate communications between the devices are created using PRNGs, or pseudo-random number generators, that produces data that's trivial to predict, the company has confirmed.
That could allow attackers to remotely tap in to communications that travel over the grids' dedicated wireless mesh networks, researchers warn. The TI microcontrollers are also used in thermostats, display panels, and other home appliances designed to work on smart grids.
"If you can figure out those keys, you essentially don't have encryption anymore," said Mike Davis, a senior security consultant for IOActive who has audited the security of smart meters. "That may mean you get to a place where it's possible to send malicious packets on the network or any number of attacks."
Joseph Reddy, a systems engineer in TI's low-power RF software group, said his team was in the process of rolling out Z-Stack version 2.3, which would replace the firmware's PRNG with a cryptographically secure RNG.
"For these types of applications, it's critical to have very secure communication because you don't want to have just anyone to be able to control all your home appliances," he told The Register.