CVE-2023-31345 in EPYC 7003 Processors
Summary
by MITRE • 02/12/2025
Improper input validation in the SMM handler may allow a privileged attacker to overwrite SMRAM, potentially leading to arbitrary code execution.
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Analysis
by VulDB Data Team • 09/24/2025
The vulnerability identified as CVE-2023-31345 represents a critical flaw in the System Management Mode SMM handler implementation that fundamentally undermines system security at the most privileged execution level. This vulnerability exists within the firmware layer of computing systems, specifically targeting the System Management Mode which operates outside the normal operating system execution context and maintains exclusive access to critical system resources. The improper input validation within the SMM handler creates a pathway for malicious actors to manipulate memory regions that should remain protected and immutable during normal system operation.
The technical flaw manifests through inadequate validation of inputs processed by the SMM handler routines, allowing an attacker with privileged access to craft malicious inputs that can traverse the normal memory protection boundaries. This vulnerability specifically enables overwrite operations within the System Management Random Access Memory which serves as a secure memory region designed to protect critical system functions and data from unauthorized access. The SMM handler's failure to properly validate input parameters creates a condition where attacker-controlled data can be interpreted and executed within the SMM context, bypassing all standard operating system security mechanisms including memory protection units and privilege levels.
The operational impact of this vulnerability is severe and potentially catastrophic for affected systems, as it provides a pathway for privilege escalation that can result in complete system compromise. An attacker who gains access to execute code within the SMM context can manipulate system memory, modify critical firmware components, and potentially establish persistent backdoors that survive operating system reboots and standard security measures. The implications extend beyond simple code execution to encompass complete system control, as SMM operates with the highest privilege level and has unrestricted access to all system resources and memory regions. This vulnerability directly aligns with CWE-20, which describes improper input validation, and represents a critical weakness in the firmware security model that can be exploited through techniques categorized under the ATT&CK framework's privilege escalation and persistence tactics.
Mitigation strategies for CVE-2023-31345 require immediate firmware updates from vendors to address the input validation deficiencies within the SMM handler components. System administrators should prioritize patching all affected systems, particularly those running on hardware from vendors who have released patches for this vulnerability. Additional protective measures include implementing memory protection features such as SMRAM locking mechanisms and ensuring that SMM handlers are properly validated through secure boot processes. Organizations should also consider monitoring for suspicious SMM activity and implementing hardware-based security features like Intel's SMEP and SMAP protections where available. The vulnerability highlights the importance of maintaining robust firmware security practices and demonstrates the critical need for comprehensive security testing of low-level system components that operate outside normal execution contexts.