CVE-2019-18216 in ROG Zephyrus M GM501GS
Summary
by MITRE
** DISPUTED ** The BIOS configuration design on ASUS ROG Zephyrus M GM501GS laptops with BIOS 313 relies on the main battery instead of using a CMOS battery, which reduces the value of a protection mechanism in which booting from a USB device is prohibited. Attackers who have physical laptop access can exhaust the main battery to reset the BIOS configuration, and then achieve direct access to the hard drive by booting a live USB OS without disassembling the laptop. NOTE: the vendor has apparently indicated that this is "normal" and use of the same battery for the BIOS and the overall system is a "new design." However, the vendor apparently plans to "improve" this an unspecified later time.
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability described in CVE-2019-18216 represents a significant design flaw in the BIOS configuration management of ASUS ROG Zephyrus M GM501GS laptops running BIOS version 313. This issue falls under the category of hardware-level security mechanisms that are critical for protecting against unauthorized system access and data breaches. The fundamental problem lies in the decision to use the main battery for maintaining BIOS configuration settings rather than implementing a dedicated CMOS battery, which is the industry standard for preserving critical system parameters. This design choice directly impacts the security posture of the device by weakening the boot integrity protection mechanisms that are essential for preventing unauthorized system modifications.
The technical flaw in this implementation creates a direct attack vector through physical access exploitation. When attackers gain physical access to the device, they can systematically drain the main battery to force a BIOS configuration reset, effectively bypassing the built-in protection mechanism that prevents booting from USB devices. This particular vulnerability is classified as a weakness in the security design pattern where the system relies on a single power source for both operational and security-critical functions. The attack methodology involves battery depletion followed by USB boot manipulation, which represents a clear violation of the principle of least privilege and proper separation of concerns in system design. This weakness can be categorized under CWE-696 as "Incorrect Behavior Order" and also relates to CWE-310 as "Cryptographic Issues" due to the improper handling of security-critical configuration data.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass broader data security implications. By allowing attackers to bypass USB boot restrictions, this flaw enables direct access to the hard drive without requiring physical disassembly of the device, which significantly reduces the barrier to entry for data theft or system compromise. The vulnerability essentially transforms a device that should be protected against unauthorized boot sources into one that can be easily compromised through relatively simple physical access attacks. This creates a dangerous situation where the device's built-in security measures become ineffective, potentially exposing sensitive user data, corporate information, or intellectual property. The attack surface expands dramatically as the system's boot integrity protection is compromised, making it susceptible to various malicious activities including malware deployment, data exfiltration, or system modification.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1014 as "Rootkit" and T1059 as "Command and Scripting Interpreter" since it enables unauthorized access that could lead to more sophisticated attacks. The vendor's acknowledgment that this is "normal" and part of a "new design" despite the security implications demonstrates a concerning lack of security awareness in product development. This approach to security design violates fundamental principles of defense in depth and proper system architecture where critical security functions should be isolated from general system operations. The fact that the vendor plans to "improve" this in an unspecified later time suggests a delayed response to security concerns rather than immediate remediation, which is problematic in the context of evolving threat landscapes and increasing cybersecurity requirements. The vulnerability also highlights the importance of proper power management design in security-critical systems, where the choice of power source for configuration data persistence should be carefully considered to prevent such bypass mechanisms. Organizations using affected devices should implement additional physical security measures and consider alternative boot protection strategies until a proper firmware update is available to address this fundamental design flaw.
The security implications of this vulnerability are particularly concerning in enterprise and government environments where device security is paramount. The ease with which this protection mechanism can be bypassed through simple battery manipulation undermines the security model of the entire device and potentially exposes organizations to significant risks. This vulnerability demonstrates the critical importance of thorough security reviews during the product development lifecycle and the need for vendors to prioritize security considerations over design convenience or cost optimization. The lack of immediate remediation from the vendor also highlights the need for organizations to maintain awareness of such design-level vulnerabilities and implement compensating controls to mitigate potential risks.