CVE-2016-5337 in QEMU
Summary
by MITRE
The megasas_ctrl_get_info function in hw/scsi/megasas.c in QEMU allows local guest OS administrators to obtain sensitive host memory information via vectors related to reading device control information.
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Analysis
by VulDB Data Team • 08/23/2022
The vulnerability identified as CVE-2016-5337 resides within the QEMU virtualization platform, specifically in the megasas_ctrl_get_info function located in the hw/scsi/megasas.c file. This flaw represents a critical information disclosure vulnerability that enables local guest operating system administrators to access sensitive host memory data through improper handling of device control information. The issue stems from inadequate input validation and memory access controls within the virtual SCSI controller implementation that manages MegaRAID storage controllers. The vulnerability affects QEMU versions prior to 2.7.0 and demonstrates how virtualization layer components can inadvertently expose host system resources to guest environments.
The technical implementation of this vulnerability exploits the megasas_ctrl_get_info function which processes control information requests from guest operating systems. When guest administrators issue specific device control commands, the function fails to properly validate or restrict memory access permissions, allowing the guest to read host memory contents through the virtualized storage controller interface. This represents a classic case of insufficient access control mechanisms where guest-level privileges escalate to host memory exposure. The flaw operates at the virtualization layer boundary where guest operating systems interact with emulated hardware components, creating an information leakage channel that bypasses normal host security boundaries.
From an operational perspective, this vulnerability poses significant risks to virtualized environments where multiple tenants share the same host infrastructure. Local guest administrators can potentially extract sensitive data including cryptographic keys, passwords, system configurations, and other confidential information stored in host memory. The impact extends beyond simple information disclosure as this data could enable further attacks such as privilege escalation, lateral movement, or complete system compromise. The vulnerability is particularly dangerous in cloud computing environments where isolation between virtual machines is paramount, as it undermines the fundamental security principle of virtual machine isolation. Attackers could leverage this information to craft more sophisticated attacks targeting other systems within the same host environment.
The vulnerability aligns with CWE-200 (Information Exposure) and represents a specific instance of improper access control in virtualized environments. It also maps to ATT&CK technique T1059 (Command and Scripting Interpreter) and T1082 (System Information Discovery) as attackers could use the leaked information to gather system details and potentially escalate privileges. Organizations using QEMU-based virtualization solutions should prioritize immediate patching to version 2.7.0 or later where the vulnerability has been addressed through proper input validation and memory access restriction mechanisms. Additional mitigations include implementing strict virtual machine isolation policies, monitoring for unusual device control requests, and considering network segmentation to limit potential exploitation scope. The fix typically involves strengthening input validation in the megasas_ctrl_get_info function and ensuring that guest requests are properly sanitized before any host memory access occurs.