ESPTouch is a connection protocol for internet of things devices. In the ESPTouchV2 protocol, while there is an option to use a custom AES key, there is no option to set the IV (Initialization Vector) prior to versions 5.3.2, 5.2.4, 5.1.6, and 5.0.8. The IV is set to zero and remains constant throughout the products lifetime. In AES/CBC mode, if the IV is not properly initialized, the encrypted output becomes deterministic, leading to potential data leakage. To address the aforementioned issues, the application generates a random IV when activating the AES key starting in versions 5.3.2, 5.2.4, 5.1.6, and 5.0.8. This IV is then transmitted along with the provision data to the provision device. The provision device has also been equipped with a parser for the AES IV. The upgrade is applicable for all applications and users of ESPTouch v2 component from ESP-IDF. As it is implemented in the ESP Wi-Fi stack, there is no workaround for the user to fix the application layer without upgrading the underlying firmware.
The product uses a broken or risky cryptographic algorithm or protocol.
Cryptographic algorithms are the methods by which data is scrambled to prevent observation or influence by unauthorized actors. Insecure cryptography can be exploited to expose sensitive information, modify data in unexpected ways, spoof identities of other users or devices, or other impacts. It is very difficult to produce a secure algorithm, and even high-profile algorithms by accomplished cryptographic experts have been broken. Well-known techniques exist to break or weaken various kinds of cryptography. Accordingly, there are a small number of well-understood and heavily studied algorithms that should be used by most products. Using a non-standard or known-insecure algorithm is dangerous because a determined adversary may be able to break the algorithm and compromise whatever data has been protected. Since the state of cryptography advances so rapidly, it is common for an algorithm to be considered “unsafe” even if it was once thought to be strong. This can happen when new attacks are discovered, or if computing power increases so much that the cryptographic algorithm no longer provides the amount of protection that was originally thought. For a number of reasons, this weakness is even more challenging to manage with hardware deployment of cryptographic algorithms as opposed to software implementation. First, if a flaw is discovered with hardware-implemented cryptography, the flaw cannot be fixed in most cases without a recall of the product, because hardware is not easily replaceable like software. Second, because the hardware product is expected to work for years, the adversary’s computing power will only increase over time.