CWE-1256 Improper Restriction of Software Interfaces to Hardware Features

The product provides software-controllable device functionality for capabilities such as power and clock management, but it does not properly limit functionality that can lead to modification of hardware memory or register bits, or the ability to observe physical side channels.

It is frequently assumed that physical attacks such as fault injection and side-channel analysis require an attacker to have physical access to the target device. This assumption may be false if the device has improperly secured power management features, or similar features. For mobile devices, minimizing power consumption is critical, but these devices run a wide variety of applications with different performance requirements. Software-controllable mechanisms to dynamically scale device voltage and frequency and monitor power consumption are common features in today's chipsets, but they also enable attackers to mount fault injection and side-channel attacks without having physical access to the device. Fault injection attacks involve strategic manipulation of bits in a device to achieve a desired effect such as skipping an authentication step, elevating privileges, or altering the output of a cryptographic operation. Manipulation of the device clock and voltage supply is a well-known technique to inject faults and is cheap to implement with physical device access. Poorly protected power management features allow these attacks to be performed from software. Other features, such as the ability to write repeatedly to DRAM at a rapid rate from unprivileged software, can result in bit flips in other memory locations (Rowhammer, [REF-1083]). Side channel analysis requires gathering measurement traces of physical quantities such as power consumption. Modern processors often include power metering capabilities in the hardware itself (e.g., Intel RAPL) which if not adequately protected enable attackers to gather measurements necessary for performing side-channel attacks from software.

• Integrity: Modify Memory, Modify Application Data, Bypass Protection Mechanism

• [Architecture and Design, Implementation] Ensure proper access control mechanisms protect software-controllable features altering physical operating conditions such as clock frequency and voltage.

• Manual Analysis: Perform a security evaluation of system-level architecture and design with software-aided physical attacks in scope. • Automated Dynamic Analysis: Use custom software to change registers that control clock settings or power settings to try to bypass security locks, or repeatedly write DRAM to try to change adjacent locations. This can be effective in extracting or changing data. The drawback is that it cannot be run before manufacturing, and it may require specialized software.

• CVE-2019-11157: Plundervolt: Improper conditions check in voltage settings for some Intel(R) Processors may allow a privileged user to potentially enable escalation of privilege and/or information disclosure via local access [REF-1081]. • CVE-2020-8694: PLATYPUS Attack: Insufficient access control in the Linux kernel driver for some Intel processors allows information disclosure. • CVE-2020-8695: Observable discrepancy in the RAPL interface for some Intel processors allows information disclosure. • CVE-2020-12912: AMD extension to a Linux service does not require privileged access to the RAPL interface, allowing side-channel attacks. • CVE-2015-0565: NaCl in 2015 allowed the CLFLUSH instruction, making Rowhammer attacks possible.