CVE-2023-4020 in GSDK
Summary
by MITRE • 12/15/2023
An unvalidated input in a library function responsible for communicating between secure and non-secure memory in Silicon Labs TrustZone implementation allows reading/writing of memory in the secure region of memory from the non-secure region of memory.
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Analysis
by VulDB Data Team • 09/25/2024
This vulnerability resides within the silicon level implementation of arm trustzone security architecture where a critical flaw exists in the communication mechanism between secure and non-secure memory regions. The vulnerability stems from insufficient validation of input parameters within a library function that manages the interface between these two memory domains. When a non-secure processor context attempts to interact with secure memory through this function, the lack of proper input validation creates a pathway for unauthorized memory access. The flaw specifically targets the trustzone implementation in silicon labs devices where the secure world operates in a protected memory space while the non-secure world functions in a less restricted environment. This architectural weakness allows malicious actors executing code in the non-secure memory region to potentially manipulate or extract data from the secure memory space through improper function calls. The vulnerability represents a fundamental breakdown in the memory isolation principles that trustzone is designed to enforce. According to the common weakness enumeration framework, this maps to cwe-20, which describes improper input validation, and more specifically cwe-125, which addresses out-of-bounds read conditions. The operational impact extends beyond simple data leakage as it can enable privilege escalation attacks where non-secure code gains access to secure kernel functions, cryptographic keys, or sensitive operational data. This flaw directly violates the fundamental security principle of memory isolation that trustzone relies upon for its security guarantees. The attack surface includes any silicon labs device utilizing trustzone technology where this library function is employed for secure communication. The implications for system security are severe as it undermines the entire trustzone architecture by allowing unauthorized access to secure memory regions. The vulnerability can be exploited by attackers who have access to the non-secure execution environment to gain information disclosure or potentially execute arbitrary code in the secure world. Mitigation strategies include firmware updates from silicon labs that implement proper input validation and parameter checking within the affected library functions. Additionally, system architects should consider implementing additional runtime monitoring to detect anomalous memory access patterns between secure and non-secure regions. The threat model aligns with attack techniques described in the attack tree framework where attackers can leverage memory corruption vulnerabilities to achieve privilege escalation. Organizations should prioritize patching affected devices and implementing security monitoring to detect potential exploitation attempts. The vulnerability also highlights the importance of proper security testing at the silicon level and adherence to security standards such as those outlined in the iso/iec 27001 framework for embedded security implementations. Regular security assessments of trustzone implementations are essential to identify similar flaws in other memory management functions that could compromise the overall security posture of the device.