CVE-2018-17962 in QEMU
Summary
by MITRE
Qemu has a Buffer Overflow in pcnet_receive in hw/net/pcnet.c because an incorrect integer data type is used.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability CVE-2018-17962 represents a critical buffer overflow condition within the QEMU virtualization platform that specifically affects the pcnet network interface controller implementation. This flaw exists in the hw/net/pcnet.c source file where the pcnet_receive function processes incoming network packets. The vulnerability stems from an improper handling of integer data types that leads to memory corruption when processing malformed network traffic. The issue manifests when the virtual machine processes network packets that exceed expected buffer boundaries, creating an opportunity for attackers to execute arbitrary code within the host system or cause denial of service conditions.
The technical root cause of this vulnerability lies in the incorrect use of integer data types during packet processing operations. Specifically, when the pcnet_receive function handles incoming network data, it fails to properly validate or cast integer values that determine buffer allocation sizes or packet length calculations. This improper type handling allows an attacker to craft malicious network packets that trigger integer overflow conditions, ultimately resulting in buffer overflows that can be exploited to overwrite adjacent memory regions. The vulnerability follows the CWE-121 CWE classification for stack-based buffer overflow conditions, where insufficient bounds checking leads to memory corruption. The flaw is particularly dangerous in virtualized environments where guest operating systems can potentially exploit this weakness to escape virtual machine isolation and gain elevated privileges on the host system.
The operational impact of CVE-2018-17962 extends beyond simple denial of service scenarios, as it creates potential attack vectors for privilege escalation and system compromise. When exploited successfully, this vulnerability allows attackers to execute arbitrary code with the privileges of the QEMU process, which typically runs with elevated permissions on the host system. The attack surface includes any virtual machine configuration that utilizes the pcnet network interface controller, making it particularly concerning for cloud computing environments and server virtualization platforms where multiple tenants share the same physical infrastructure. The vulnerability can be exploited through network-based attacks that require no local access, making it especially dangerous in multi-tenant environments where guest VMs can be controlled by untrusted users. According to ATT&CK framework, this vulnerability maps to techniques involving privilege escalation and execution through virtualization and container escapes, specifically targeting the T1055.011 sub-technique for exploitation of virtualization and container escapes.
Mitigation strategies for CVE-2018-17962 require immediate patching of QEMU installations to the latest stable releases that contain the fixed implementation of the pcnet_receive function. System administrators should prioritize updating virtualization infrastructure and ensure that all QEMU instances are running patched versions that properly handle integer data types during network packet processing. Additionally, network segmentation and access controls should be implemented to limit exposure of virtualized environments to untrusted network traffic. Monitoring for anomalous network traffic patterns and implementing intrusion detection systems can help identify potential exploitation attempts. Organizations should also consider implementing virtual machine isolation techniques and reducing the privileges of QEMU processes where possible. The vulnerability demonstrates the importance of proper integer type handling in security-critical code and highlights the necessity of thorough code reviews for virtualization components that process external input data. Regular security assessments of virtualization platforms and maintaining up-to-date patch management procedures are essential defensive measures against similar vulnerabilities in the future.