CVE-2012-0029 in qemu-kvm
Summary
by MITRE
Heap-based buffer overflow in the process_tx_desc function in the e1000 emulation (hw/e1000.c) in qemu-kvm 0.12, and possibly other versions, allows guest OS users to cause a denial of service (QEMU crash) and possibly execute arbitrary code via crafted legacy mode packets.
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Analysis
by VulDB Data Team • 11/29/2021
The CVE-2012-0029 vulnerability represents a critical heap-based buffer overflow affecting the e1000 network interface emulation within QEMU-KVM virtualization environments. This flaw exists within the process_tx_desc function located in the hw/e1000.c file, making it particularly dangerous as it operates at the hardware emulation layer where guest operating systems interact with virtualized network devices. The vulnerability specifically impacts QEMU-KVM version 0.12 and potentially other versions, creating a widespread risk across numerous virtualized environments that rely on this network emulation component.
The technical implementation of this vulnerability stems from inadequate input validation within the e1000 emulation code, particularly when processing legacy mode packets transmitted from guest operating systems. When maliciously crafted packets are sent through the virtualized network interface, the process_tx_desc function fails to properly bounds-check data before copying it into heap-allocated buffers. This oversight creates a condition where attacker-controlled data can overwrite adjacent memory locations, potentially corrupting heap metadata or executable code. The heap-based nature of the overflow means that the vulnerability can be exploited to manipulate heap structures, leading to unpredictable behavior including program crashes or more severe code execution capabilities.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can potentially enable arbitrary code execution within the host system. When guest operating systems transmit specially crafted packets, the buffer overflow can be leveraged to overwrite function pointers, return addresses, or other critical memory structures, potentially allowing attackers to execute malicious code with the privileges of the QEMU process. This presents a significant risk in multi-tenant virtualized environments where isolation between guest VMs is compromised, as successful exploitation could lead to privilege escalation and complete system compromise. The vulnerability affects not only the stability of individual virtual machines but also the integrity of the entire virtualization infrastructure.
Mitigation strategies for CVE-2012-0029 should prioritize immediate patching of affected QEMU-KVM installations to the latest stable versions containing the necessary memory validation fixes. Organizations should also implement network segmentation and access controls to limit exposure to potentially malicious traffic, particularly in environments where untrusted guest operating systems are present. The vulnerability aligns with CWE-121, heap-based buffer overflow, and can be mapped to ATT&CK technique T1059 for command and control through code injection. Additional defensive measures include monitoring for anomalous packet patterns, implementing network intrusion detection systems, and maintaining regular vulnerability assessments of virtualization infrastructure to identify similar weaknesses in other emulated hardware components.