CVE-2019-9547 in Storage Performance Development Kit
Summary
by MITRE
In Storage Performance Development Kit (SPDK) before 19.01, a malicious vhost client (i.e., virtual machine) could carefully construct a circular descriptor chain that would result in a partial denial of service in the SPDK vhost target, because the vhost target did not properly detect such chains.
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability identified as CVE-2019-9547 affects the Storage Performance Development Kit (SPDK) version 19.01 and earlier, representing a critical security flaw in the vhost target implementation that enables malicious virtual machine clients to exploit a specific memory management weakness. This vulnerability resides within the virtual host subsystem that facilitates communication between virtual machines and SPDK storage backends, creating a potential attack surface where untrusted vhost clients can manipulate descriptor chains to disrupt normal operations. The SPDK vhost target serves as a crucial component in virtualized storage environments, handling I/O operations for virtualized block devices and maintaining the integrity of data transfer mechanisms between guest operating systems and underlying storage resources.
The technical flaw manifests through the improper detection of circular descriptor chains within the vhost target's memory management system. When a malicious vhost client constructs a carefully crafted circular reference within the descriptor chain structure, the vhost target fails to validate the chain integrity properly, leading to a partial denial of service condition. This vulnerability stems from insufficient validation mechanisms that should have detected the circular references during descriptor chain processing, allowing the malicious client to create an infinite loop or resource exhaustion scenario that impacts the target's ability to process legitimate I/O requests. The vulnerability specifically affects the vhost target's handling of memory descriptors used in virtio-based I/O operations, where descriptor chains are fundamental data structures that define the sequence of data buffers to be processed.
The operational impact of this vulnerability extends beyond simple service disruption, as it allows malicious virtual machine clients to consume excessive system resources and potentially cause system instability within SPDK deployments. The partial denial of service means that while the system may not completely crash, legitimate I/O operations can be significantly degraded or blocked, affecting storage performance and availability for all connected clients. This vulnerability is particularly concerning in virtualized environments where multiple VMs share the same SPDK vhost target, as a single compromised or malicious guest can impact the entire storage infrastructure. The attack vector requires minimal privileges within the virtual machine environment and can be executed through normal vhost communication protocols, making it an attractive target for attackers seeking to disrupt storage services.
Mitigation strategies for CVE-2019-9547 primarily involve upgrading to SPDK version 19.01 or later, which includes proper validation mechanisms for descriptor chain integrity. Organizations should implement strict monitoring of vhost target performance metrics to detect unusual resource consumption patterns that may indicate exploitation attempts. The fix addresses the core issue by implementing comprehensive circular chain detection algorithms that validate descriptor chain structures before processing them, preventing malicious clients from creating infinite loops. This vulnerability aligns with CWE-691, which covers insufficient control flow management, and corresponds to techniques described in the MITRE ATT&CK framework under T1499, specifically for network denial of service attacks targeting storage systems. Security teams should also consider implementing network segmentation and access controls to limit vhost client privileges and reduce the potential impact of such attacks within their virtualized storage environments.