CVE-2019-5673 in Tegra Kernel Driver
Summary
by MITRE
NVIDIA Tegra kernel driver contains a vulnerability in the ARM System Memory Management Unit (SMMU) where an improper check for a fault condition causes transactions to be discarded, which may lead to denial of service. The updates apply to all versions prior to and including R28.3.
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Analysis
by VulDB Data Team • 05/29/2020
The vulnerability identified as CVE-2019-5673 resides within the NVIDIA Tegra kernel driver's implementation of the ARM System Memory Management Unit functionality, representing a critical flaw in the memory management subsystem of embedded systems. This issue affects all NVIDIA Tegra processor variants running software versions prior to and including R28.3, creating a persistent security concern across various mobile and embedded platforms where these processors are deployed. The vulnerability manifests specifically within the SMMU's fault handling mechanism, where the driver fails to properly validate fault conditions before processing memory transactions.
The technical flaw stems from an inadequate validation routine that does not sufficiently verify the state of memory transactions when fault conditions occur during the SMMU processing. When a fault condition is detected, the kernel driver should properly handle the transaction by either completing it appropriately or discarding it with proper error reporting. However, the current implementation contains a logic error where the driver fails to properly check for fault conditions, leading to transactions being silently discarded rather than being properly managed or reported. This improper handling creates a scenario where legitimate memory operations may be lost or corrupted, potentially affecting system stability and security.
The operational impact of this vulnerability extends beyond simple system instability to create potential denial of service conditions that could compromise the availability of critical system functions. When transactions are discarded due to the improper fault handling, it can lead to application crashes, system hangs, or complete system failures depending on the nature of the discarded operations. The vulnerability is particularly concerning in embedded systems where system reliability is paramount, as it can affect the operation of critical services such as security features, communication protocols, or real-time processing functions. Additionally, the vulnerability may provide attackers with opportunities to perform denial of service attacks against devices running affected Tegra processors, potentially disrupting service availability for extended periods.
The vulnerability aligns with CWE-252, which describes an "Unchecked Return Value" where the system fails to properly validate or handle return values from system calls or memory operations. From an ATT&CK framework perspective, this vulnerability could be leveraged in a denial of service attack pattern, potentially classified under T1499.004 for Network Denial of Service, where an attacker could exploit the SMMU fault handling flaw to disrupt system availability. The vulnerability also relates to T1070.006 for Indicator Removal on Host, as the improper handling of fault conditions may mask underlying system issues that could be exploited by attackers. Organizations should prioritize updating their Tegra-based systems to versions beyond R28.3 to remediate this vulnerability, as the affected systems may be particularly susceptible to exploitation in environments where continuous system availability is critical. The mitigation strategy should include comprehensive system updates, proper validation of memory transaction handling, and implementation of monitoring mechanisms to detect potential fault condition mismanagement.