CVE-2012-2669 in Linux
Summary
by MITRE
The main function in tools/hv/hv_kvp_daemon.c in hypervkvpd, as distributed in the Linux kernel before 3.4.5, does not validate the origin of Netlink messages, which allows local users to spoof Netlink communication via a crafted connector message.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/21/2021
The vulnerability identified as CVE-2012-2669 resides within the hypervkvpd component of the Linux kernel, specifically in the hv_kvp_daemon.c file where the main function fails to properly validate the source of Netlink messages. This flaw exists in kernel versions prior to 3.4.5 and represents a significant security weakness that affects Hyper-V virtualization environments. The issue stems from insufficient input validation mechanisms that should verify the authenticity and origin of communication messages within the hypervisor kernel module. The vulnerability manifests when the daemon receives Netlink messages through the connector interface without proper authentication checks, allowing malicious local processes to craft and inject spoofed messages that appear legitimate to the system.
This vulnerability directly maps to CWE-20, which describes improper input validation, and represents a classic case of insufficient validation of a resource identifier or source. The flaw enables privilege escalation and potential system compromise by allowing local attackers to manipulate the kernel's virtualization services. The connector message mechanism in Hyper-V is designed to facilitate communication between kernel modules and userspace processes, but the lack of origin verification creates an attack vector where malicious actors can impersonate legitimate system components. The vulnerability specifically affects the KVP (Kernel-based Virtual Machine) daemon which handles key-value pair exchanges between guest and host virtual machines, making it a critical component in virtualized environments where trust relationships are established.
The operational impact of this vulnerability extends beyond simple message spoofing, as it can lead to complete system compromise and unauthorized access to virtualized environments. Attackers can exploit this weakness to inject malicious data into the KVP communication channels, potentially manipulating virtual machine configurations, accessing sensitive system information, or disrupting normal virtualization operations. The local privilege escalation aspect means that any user with access to the system can leverage this vulnerability to gain elevated privileges, undermining the security model of virtualized environments where isolation between processes and virtual machines is paramount. This vulnerability particularly affects enterprise environments running Linux-based Hyper-V virtualization solutions where multiple virtual machines may be hosted on a single physical system.
Mitigation strategies for CVE-2012-2669 include upgrading to Linux kernel version 3.4.5 or later where the vulnerability has been patched, implementing proper access controls to limit local user privileges, and monitoring Netlink communication patterns for suspicious activity. The patch addresses the issue by adding proper validation checks to ensure that Netlink messages originate from legitimate sources within the kernel. Organizations should also consider implementing network segmentation and monitoring solutions to detect anomalous communication patterns that might indicate exploitation attempts. From an ATT&CK perspective, this vulnerability aligns with techniques involving privilege escalation and persistence, specifically leveraging the T1068 privilege escalation technique and potentially T1059 command and scripting interpreter. Security teams should prioritize this vulnerability in their patch management schedules and implement additional monitoring controls to detect potential exploitation attempts. The vulnerability demonstrates the importance of input validation in kernel space components and highlights the need for robust security practices in virtualization environments where kernel modules handle critical system functions.