CVE-2015-3214 in QEMU
Summary
by MITRE
The pit_ioport_read in i8254.c in the Linux kernel before 2.6.33 and QEMU before 2.3.1 does not distinguish between read lengths and write lengths, which might allow guest OS users to execute arbitrary code on the host OS by triggering use of an invalid index.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/21/2024
The vulnerability identified as CVE-2015-3214 represents a critical flaw in the Linux kernel's i8254 timer implementation and QEMU virtualization software that enables privilege escalation from guest operating systems to host systems. This vulnerability specifically affects the pit_ioport_read function within the i8254.c file, which handles programmable interval timer port operations. The flaw stems from an insufficient validation mechanism that fails to properly differentiate between read and write operations, creating a path for malicious code execution.
The technical root cause of this vulnerability lies in the improper handling of I/O port operations within the virtual timer subsystem. When a guest operating system attempts to read from specific timer ports, the kernel's pit_ioport_read function does not adequately verify the operation type or length parameters. This lack of proper validation allows attackers to craft malicious I/O requests that manipulate internal data structures, potentially leading to memory corruption and arbitrary code execution. The vulnerability operates at the hardware abstraction layer where guest systems interact with virtualized timer hardware, making it particularly dangerous in virtualized environments.
The operational impact of CVE-2015-3214 is severe and far-reaching, particularly in cloud computing and virtualization environments where multiple guest operating systems share the same host infrastructure. An attacker with access to a guest OS can exploit this vulnerability to execute arbitrary code with host privileges, effectively breaking out of the virtual machine isolation boundary. This represents a classic privilege escalation attack that can lead to complete host compromise, data exfiltration, and potential lateral movement within the network infrastructure. The vulnerability affects systems running Linux kernel versions prior to 2.6.33 and QEMU versions before 2.3.1, making it particularly relevant to older virtualized environments that may not have received timely updates.
This vulnerability aligns with CWE-125: Out-of-Bounds Read and CWE-787: Out of Bounds Write, as the improper validation leads to memory access violations that can be exploited for code execution. From an ATT&CK framework perspective, this vulnerability maps to T1059.007: Command and Scripting Interpreter: PowerShell and T1068: Exploitation for Privilege Escalation, as it provides a pathway for attackers to elevate their privileges within the system. The attack vector typically involves guest-to-host privilege escalation through virtualization layer manipulation, which is classified under T1548.003: Abuse of Cloud Service Root Credentials in cloud environments. Organizations should implement immediate mitigations including updating to patched kernel versions, applying QEMU patches, and implementing network segmentation to limit the potential impact of such vulnerabilities.
The remediation strategy for CVE-2015-3214 requires comprehensive system updates across both kernel and virtualization layers. System administrators must upgrade to Linux kernel 2.6.33 or later versions and ensure QEMU installations are updated to version 2.3.1 or higher. Additionally, organizations should consider implementing virtualization security measures such as disabling unnecessary I/O port access, applying security patches regularly, and monitoring for suspicious I/O operations within virtualized environments. The vulnerability demonstrates the critical importance of proper input validation and the potential consequences when hardware abstraction layers fail to properly enforce security boundaries between virtualized components.