The ESP32 "backdoor" that wasn't | Dark Mentor LLC
This post refutes the claim that researchers found a "backdoor" in ESP32 Bluetooth chips. What the researchers highlight (vendor-specific HCI commands to read & write controller memory) is a common design pattern found in other Bluetooth chips from other vendors as well, such as Broadcom, Cypress, a...
I tried to offer a gentler backgrounder on this HCI business: https://lemmy.ml/comment/17160273
The opcodes that actually jumped out at me more than the undocumented ones were the ones that erases the flash.
But the conclusion stands. None of this is a 'backdoor' unless you can secretly access it from the wireless side and nothing in the presentation points to that. If I had to guess, the opcodes are for QA and tuning on the manufacturing line.
Finally, some technical details that were sorely lacking from yesterday's article.
Anyway, having direct unprivileged R/W access to platform memory is indeed a security hole, no matter the vendor.
Anyway, having direct unprivileged R/W access to platform memory is indeed a security hole, no matter the vendor.
It is not. ESP32 is an embedded chip with less than one megabyte of RAM. It cannot run apps or load websites with any malicious code, it only runs the firmware that you flash on it, nothing else, and of course your firmware has full access to every chip feature. If your firmware has a security hole, it's not the chip's fault.
I mean, this doesn't really change anything from a practical perspective. It just highlights that the verbage in the press release was alarmist.
It's still a security concern that most users will be unaware of.
Overall we at Dark Mentor do consider the use of VSCs granting the capability to read and write memory, flash, or registers to be bad security design. It’s bad design for Espressif the same as it’s bad design for Broadcom, Texas Instruments, and any other vendor that uses it. This issue is now being tracked as CVE-2025-27840.
Thanks. I was looking for an explanation like this
But but it's Chinese and Chinese tech bad
Potato, potato....
Whether we call them 'undocumented commands' or a 'backdoor', the affect is more or less the same; a series of high-level commands not listed within the specs, preventing systems engineers/designers from planning around vulnerabilities and their potential for malicious use.
I don't get the downvotes, wether you call it backdoor or private API it's a security hole, and nitpicking on its name won't help fixing it.
It was all positive until the guy below me came in throwing insults. Then people started piling downvotes on both....
In that case, every stack that you use is riddled with those and we are all hosed. And yet somehow your computer, your phone and the internet keep on working most of the time.
The dude that wrote this blog is a goof....
defines backdoor as “relating to something that is done secretly
effectively constitute a “private API”, and a company’s choice to not publicly document their private API
Idiot thinks these are two different things....
Are they are trying to argue that malicious intent is needed to define it as a back door?
Moron..
A backdoor requires malicious intent, otherwise it's just a vulnerability
You’re very smart. I didn’t realize that until you called someone a goof, idiot and moron, but now it’s very clear that you have far superior intelligence.
