Ethical Hacking News
Researchers uncover an undocumented backdoor in a billion-dollar Bluetooth chip, highlighting the need for increased vigilance in IoT device security. The discovery raises concerns about the potential risks associated with widespread adoption of this technology, emphasizing the importance of proactive threat mitigation strategies.
The ESP32 microchip contains an undocumented backdoor with hidden vendor-specific commands. These commands allow low-level control over Bluetooth functions, enabling memory manipulation, MAC address spoofing, and packet injection. 29 undocumented commands were discovered by Spanish researchers, collectively forming a "backdoor" that enables potential exploitation for unauthorized access or manipulation. The risks associated with these commands are significant, particularly in the context of IoT devices, where an attacker could spoof trusted devices, access unauthorized data, pivot to other devices, or establish long-term persistence.
The world of technology is constantly evolving, and with it, new vulnerabilities are being discovered. A recent find has shed light on an undocumented backdoor found in the widely used ESP32 microchip, which is utilized by over 1 billion devices as of 2023. This revelation raises concerns about the security of IoT devices and highlights the need for continued vigilance in the field of cybersecurity.
The ESP32 microchip, developed by Chinese manufacturer Espressif, has become a staple in many devices, from smart home appliances to wearables and industrial equipment. Its widespread adoption is due to its versatility and affordability, making it an attractive choice for manufacturers. However, this ubiquity also raises concerns about the potential risks associated with such a widely used component.
In recent months, Spanish researchers Miguel Tarascó Acuña and Antonio Vázquez Blanco of Tarlogic Security discovered an undocumented backdoor in the ESP32 microchip. This finding was presented at the RootedCON conference in Madrid, where the researchers detailed their research and the potential implications of this discovery.
According to Tarlogic, the ESP32 Bluetooth chip contains hidden vendor-specific commands (Opcode 0x3F) that allow low-level control over Bluetooth functions. These commands were not publicly documented by Espressif, suggesting either that they were never intended for public use or were left in by mistake during the development process.
The researchers found a total of 29 undocumented commands, which collectively can be characterized as a "backdoor" that enables memory manipulation (read/write RAM and Flash), MAC address spoofing (device impersonation), and LMP/LLCP packet injection. This means that an attacker could potentially exploit this backdoor to gain unauthorized access to the device, manipulate its behavior, or even establish long-term persistence.
The risks associated with these commands are significant, particularly in the context of IoT devices. If an attacker gains control over a device using one of these commands, they may be able to:
* Spoof trusted devices and impersonate legitimate connections
* Access unauthorized data within the device's RAM or Flash memory
* Pivot to other devices on the network, potentially establishing a backdoor for further attacks
* Establish long-term persistence in the device's system, allowing for repeated exploitation
Tarlogic warned that these commands could be leveraged by malicious actors, including those with OEM-level access or supply chain attack capabilities. This highlights the potential risks associated with IoT devices, which often rely on complex networks of interconnected components.
In light of this discovery, Espressif has not publicly commented on the matter. However, it is clear that the security implications of this backdoor cannot be ignored. As the world continues to move forward in the realm of technology, it is crucial for manufacturers and consumers alike to remain vigilant about the potential vulnerabilities lurking within widely used components.
In recent years, numerous high-profile breaches have highlighted the importance of robust cybersecurity measures. The discovery of this undocumented backdoor serves as a stark reminder that even seemingly secure technologies can harbor hidden risks. As we move forward into an increasingly interconnected world, it is essential to prioritize security awareness and proactive threat mitigation strategies.
By shedding light on this vulnerability, Tarlogic has provided a valuable service to the cybersecurity community. Their research underscores the need for continued vigilance in monitoring the ever-evolving landscape of technology. It also highlights the importance of manufacturer accountability and proactive measures to address potential vulnerabilities before they can be exploited by malicious actors.
In conclusion, the discovery of an undocumented backdoor in the ESP32 microchip serves as a timely reminder of the importance of cybersecurity awareness and proactive threat mitigation strategies. As we continue to navigate the complexities of our increasingly interconnected world, it is crucial that manufacturers, consumers, and security experts alike remain vigilant about potential vulnerabilities lurking within widely used technologies.
Editorial - 03/10/2025 - 11:45am:
There is chatter about this not being as serious of an issue as claimed by Tarlogic Security as it likely can't be exploited remotely (i.e. wirelessly via Bluetooth) unless there are issues in the drivers or software that can be exploited when interacting with the computer via Bluetooth - which is not an impossible scenario, even if the security bugs in the drivers/software are unintentional. Another concern, there could be collusion between some seemingly legitimate driver/software vendor(s), state sponsored malicious software developers, and the hardware vendor (encouraged by a nation state) to create a very difficult to detect backdoor that can only be exploited using certain drivers or software, or even custom malicious software (malware) that conducts nefarious activity via the Bluetooth device intentionally to evade detection. Those scenarios, albeit not impossible, are less likely than the hardware vendor simply forgetting to remove debugging functionality prior to shipping. All that being said, regarding accessing the hidden functionality solely by itself, the chatter appears to be leaning towards this: if you can access the hidden functionality in the Bluetooth hardware that is accessible via the Host Controller Interface (HCI), you already "own" the computer and therefore could have done all of that stuff and more via many other means anyway. We will stay on top of this, and we will keep you informed if evidence is presented to the contrary and this turns out to be a legitimately serious backdoor, especially if certain drivers/software/malware are found to be accessing the hidden functionality. However, at this time, MITRE has rated this issue a medium severity vulnerability in CVE-2025-27840 and the severity remains unscored by NIST.
Related Information:
https://www.ethicalhackingnews.com/articles/The-Hidden-Vulnerability-Undocumented-Backdoor-Found-in-Ubiquitous-Bluetooth-Chip-Used-by-a-Billion-Devices-ehn.shtml
https://www.bleepingcomputer.com/news/security/undocumented-backdoor-found-in-bluetooth-chip-used-by-a-billion-devices/
https://nvd.nist.gov/vuln/detail/CVE-2025-27840
Originally Published: Sat Mar 8 11:39:00 2025 by llama3.2 3B Q4_K_M
