CVE-2021-25407 in NPU Driver
Summary
by MITRE • 06/11/2021
A possible out of bounds write vulnerability in NPU driver prior to SMR JUN-2021 Release 1 allows arbitrary memory write.
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Analysis
by VulDB Data Team • 06/14/2021
The vulnerability identified as CVE-2021-25407 represents a critical out-of-bounds write flaw within the Neural Processing Unit driver component of a proprietary hardware platform. This issue affects systems prior to the SMR JUN-2021 Release 1 version, indicating that the vulnerability existed in earlier firmware implementations and was subsequently patched. The nature of this vulnerability allows an attacker to execute arbitrary memory writes, which fundamentally compromises the system's memory integrity and potentially enables privilege escalation or code execution in the kernel space.
This vulnerability falls under the CWE-787 category of out-of-bounds write conditions, specifically manifesting as an improper access to memory locations beyond the allocated buffer boundaries. The flaw occurs within the NPU driver which handles neural processing operations, suggesting that the vulnerability could be exploited through malicious neural network operations or data processing sequences that trigger the flawed memory management routine. The out-of-bounds write condition typically arises when input validation fails to properly check array indices or buffer sizes, allowing attackers to write data beyond intended memory allocation boundaries.
The operational impact of this vulnerability extends beyond simple memory corruption, as it enables arbitrary memory write capabilities that can be leveraged for privilege escalation attacks. An attacker who successfully exploits this vulnerability could potentially overwrite critical system structures, kernel memory regions, or even inject malicious code into the running system. This capability directly aligns with ATT&CK technique T1068 which covers 'Local Privilege Escalation' and T1059 which covers 'Command and Scripting Interpreter', as the arbitrary write capability could be used to modify system binaries or runtime memory to achieve persistent access or execute malicious payloads.
The exploitation of this vulnerability requires careful crafting of input data that causes the NPU driver to access memory locations beyond allocated buffers, potentially through malformed neural processing commands or data structures. The attack surface is particularly concerning given that the NPU driver operates at a privileged level within the system architecture, meaning successful exploitation could provide attackers with elevated system privileges. Security researchers should note that this vulnerability represents a significant risk to systems utilizing neural processing hardware, particularly those deployed in environments where untrusted input processing occurs, such as AI inference servers or edge computing devices with neural processing capabilities.
Mitigation strategies for CVE-2021-25407 should prioritize immediate firmware updates to the SMR JUN-2021 Release 1 or later versions where the vulnerability has been patched. System administrators should implement network segmentation and access controls to limit exposure of systems running affected NPU driver versions. Additional protective measures include monitoring for unusual memory access patterns or privilege escalation attempts, implementing kernel memory protection features such as address space layout randomization, and ensuring that only trusted code executes on systems containing affected hardware. The vulnerability highlights the importance of thorough input validation and bounds checking in kernel drivers, particularly those handling specialized processing workloads such as neural network computations.