CVE-2012-5532 in Linux
Summary
by MITRE
The main function in tools/hv/hv_kvp_daemon.c in hypervkvpd, as distributed in the Linux kernel before 3.8-rc1, allows local users to cause a denial of service (daemon exit) via a crafted application that sends a Netlink message. NOTE: this vulnerability exists because of an incorrect fix for CVE-2012-2669.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability described in CVE-2012-5532 affects the hypervkvpd daemon component within the Linux kernel, specifically in the tools/hv/hv_kvp_daemon.c file. This daemon serves as a critical component in Hyper-V virtualization environments, responsible for managing key value pairs that facilitate communication between virtual machines and their host systems. The daemon operates as a background service that handles Netlink messages, which are essential for kernel-user space communication in Linux systems. The flaw manifests in the main function's handling of incoming Netlink messages, creating a potential attack vector that could disrupt the daemon's operation and thereby impact virtual machine functionality.
The technical implementation of this vulnerability stems from an incorrect fix applied to CVE-2012-2669, demonstrating how remediation efforts can sometimes introduce new security weaknesses. The daemon fails to properly validate or sanitize incoming Netlink messages, allowing a local attacker to craft malicious payloads that trigger an unexpected termination of the hypervkvpd process. This improper message handling creates a condition where the daemon exits abruptly, leading to a denial of service scenario that affects the entire virtualization infrastructure. The vulnerability specifically targets the message processing logic within the main function, where insufficient input validation permits crafted Netlink messages to cause memory corruption or other internal errors that result in process termination.
The operational impact of this vulnerability extends beyond simple daemon crashes, as it can severely compromise the stability and availability of Hyper-V virtualized environments. When the hypervkvpd daemon terminates unexpectedly, it disrupts the key value pair exchange mechanism that virtual machines rely upon for proper configuration and communication with host systems. This disruption can lead to virtual machine misconfigurations, loss of connectivity, and potential service interruptions that affect business continuity. The local privilege requirement means that attackers must already have access to the system to exploit this vulnerability, but the impact remains significant as it can be leveraged to create persistent denial of service conditions that may be difficult to detect and remediate.
This vulnerability aligns with CWE-20, which addresses "Improper Input Validation," and demonstrates the importance of thorough testing when implementing security fixes. The issue also relates to ATT&CK technique T1499.004, which covers "Cloud Service Disruption," as the daemon's termination affects virtualization services. The improper handling of Netlink messages represents a classic buffer overflow or memory corruption scenario, where the daemon's failure to properly validate message structure leads to unintended program termination. Organizations running Linux kernels prior to version 3.8-rc1 should prioritize immediate patching to address this vulnerability, as the remediation requires updating the kernel to a version that properly handles Netlink message validation. The vulnerability highlights the critical need for comprehensive testing of security patches to prevent regressions that may introduce new attack vectors while addressing existing threats.