Introduction to Usbliter8 Exploit
A European cybersecurity research firm, Paradigm Shift, has disclosed details of a new BootROM exploit that affects millions of iPhones and cannot be patched with a software update. The exploit, dubbed Usbliter8, targets Apple’s SecureROM, which is the first code an iPhone runs on startup and the foundation of Apple’s entire secure boot chain.
How Usbliter8 Works
Usbliter8 chains a USB controller bug and a device firmware configuration weakness, requiring physical USB access to the targeted device. The exploit works against iPhones with A12 and A13 chips, including iPhone XS, XR, and 11, as well as Apple Watches with S4 and S5 chips. These affected chips were released in 2018 and 2019.
To conduct a Usbliter8 attack, an attacker must connect a special USB device, such as a Raspberry Pi Pico 2 or similar microcontroller board, to the targeted iPhone and send it crafted USB setup packets. This triggers an out-of-bounds write, allowing the attacker to overwrite critical data in memory and ultimately take control of the processor, escalate privileges, and execute arbitrary code with full system privileges.
Impact of Usbliter8
Although the exploit cannot directly be used to access user data, it opens up wider attack vectors to compromise the Secure Enclave, a separate security processor that protects user data. The impact of Usbliter8 is similar to that of Checkm8, the 2019 BootROM exploit that left an entire generation of iPhones permanently vulnerable to jailbreak.
Paradigm Shift noted that while an attack cannot be launched remotely, such an exploit could be highly useful to forensics vendors. The security firm has released PoC code for the Usbliter8 exploit, aiming to document the real-world impact of this class of hardware vulnerabilities and contribute to the broader understanding of modern BootROM security.
Apple's Response
Paradigm Shift reported the findings to Apple before disclosure, but the tech giant has not publicly responded to the research. However, Apple told SecurityWeek that its devices are designed with multiple layers of security to protect against a wide range of potential threats, and pointed out that iPhone, iPad, and Watch models with A14/S6 or newer chips are not affected, and neither are any Mac devices.
Apple also noted that the Usbliter8 exploit does not bypass data protection mechanisms, and user information such as files, photos, or messages cannot be directly accessed via exploitation of this vulnerability. The company appreciates the researchers sharing their work, although the vulnerability was fixed years before this research in its newer devices.
Conclusion
The Usbliter8 exploit highlights the importance of hardware security and the potential risks associated with BootROM vulnerabilities. As the cybersecurity landscape continues to evolve, it is essential for device manufacturers to prioritize security and for users to stay informed about potential threats to their devices.
- Paradigm Shift has disclosed details of a new BootROM exploit called Usbliter8.
- The exploit affects millions of iPhones and cannot be patched with a software update.
- Usbliter8 targets Apple’s SecureROM and requires physical USB access to the targeted device.
- The exploit works against iPhones with A12 and A13 chips, as well as Apple Watches with S4 and S5 chips.
- Conducting a Usbliter8 attack involves connecting a special USB device to the targeted iPhone and sending it crafted USB setup packets.
- The attack triggers an out-of-bounds write, allowing the attacker to overwrite critical data in memory and ultimately take control of the processor.
- The exploit opens up wider attack vectors to compromise the Secure Enclave, a separate security processor that protects user data.
By publishing this research and the accompanying proof of concept, we aim to document the real-world impact of this class of hardware vulnerabilities, contribute to the broader understanding of modern BootROM security, and demonstrate that even recent SecureROM generations remain susceptible to subtle hardware flaws.
Source: SecurityWeek