CVE-2022-23822 in Zynq-7000
Summary
by MITRE • 04/27/2022
In this physical attack, an attacker may potentially exploit the Zynq-7000 SoC First Stage Boot Loader (FSBL) by bypassing authentication and loading a malicious image onto the device. This in turn may further allow the attacker to perform additional attacks such as such as using the device as a decryption oracle. An anticipated mitigation via a 2022.1 patch will resolve the issue.
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Analysis
by VulDB Data Team • 04/30/2022
The vulnerability identified as CVE-2022-23822 affects the Zynq-7000 System-on-Chip (SoC) First Stage Boot Loader (FSBL) which represents a critical security weakness in the hardware initialization process. This issue resides within the physical attack surface of embedded systems, specifically targeting the initial boot phase where device authenticity and integrity are established. The FSBL serves as the first line of defense in the boot process, responsible for authenticating and loading subsequent boot stages of the operating system, making it a prime target for attackers seeking persistent control over embedded devices. The vulnerability stems from insufficient authentication mechanisms within the boot loader that allow unauthorized parties to bypass security checks and load malicious firmware images.
The technical flaw manifests in the FSBL's failure to properly validate the authenticity of boot images during the initial loading phase, creating an attack vector where adversaries can inject malicious code without proper authorization. This weakness directly relates to CWE-284, which addresses inadequate access control mechanisms, and specifically targets the boot process security controls that should prevent unauthorized modifications to the device's firmware. The vulnerability operates at the hardware level rather than the software level, making it particularly concerning as it bypasses traditional software-based security measures and operates at a fundamental system level where access control should be paramount. Attackers exploiting this vulnerability can potentially load malicious images that enable further attacks including decryption oracle operations, which can compromise the entire cryptographic security infrastructure of the device.
The operational impact of this vulnerability extends far beyond the initial unauthorized boot process, as it creates persistent access points that can be leveraged for advanced persistent threats. When an attacker successfully loads malicious code through this vulnerability, they gain a foothold that can be used to perform additional attacks such as using the device as a decryption oracle, which can expose sensitive cryptographic keys and data. This capability represents a significant threat to systems that rely on the Zynq-7000 SoC for security-critical applications, particularly in industrial control systems, network infrastructure, and embedded security devices. The attack can be executed without requiring physical access to the device's secure elements, making it particularly dangerous in environments where physical security measures may be inadequate.
The mitigation strategy for this vulnerability involves applying the 2022.1 patch release which addresses the authentication bypass issue within the FSBL implementation. This patch represents a firmware-level fix that strengthens the boot loader's authentication mechanisms and ensures proper validation of boot images before loading. Organizations should implement this patch as a priority, as the vulnerability provides attackers with a pathway to establish persistent control over affected devices. The fix aligns with security best practices outlined in the NIST Cybersecurity Framework and addresses specific threats identified in the MITRE ATT&CK framework under the boot process and persistence tactics. Given the nature of the vulnerability, system administrators should also conduct comprehensive inventory assessments to identify all affected Zynq-7000 SoC devices and verify that the patch has been successfully applied to prevent exploitation attempts.