CVE-2018-17958 in QEMU
Summary
by MITRE
Qemu has a Buffer Overflow in rtl8139_do_receive in hw/net/rtl8139.c because an incorrect integer data type is used.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability identified as CVE-2018-17958 represents a critical buffer overflow condition within the QEMU virtualization platform's implementation of the RTL8139 network adapter driver. This issue manifests in the rtl8139_do_receive function located within the hw/net/rtl8139.c source file, where improper handling of integer data types creates a pathway for malicious input to overwrite adjacent memory regions. The vulnerability specifically arises from the use of an incorrect integer data type during packet processing, which allows an attacker to potentially manipulate the size calculation used for buffer allocation and data copying operations.
The technical flaw stems from a fundamental type mismatch in the network packet processing logic where a smaller integer type is employed to store data that exceeds the allocated storage capacity. This incorrect data type usage directly enables an attacker to craft specially formatted network packets that, when processed by the affected QEMU instance, trigger the buffer overflow condition. The vulnerability exists in the context of virtual machine network communication where guest operating systems transmit network traffic through the emulated RTL8139 network adapter, making it exploitable through network-based attacks against virtualized environments.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can potentially enable remote code execution within the context of the QEMU process. Attackers leveraging this vulnerability can manipulate the memory layout of the virtualization environment, potentially leading to privilege escalation, guest-to-host breakout scenarios, or complete system compromise depending on the execution environment. The vulnerability affects any QEMU installation utilizing the RTL8139 network adapter emulation, making it particularly concerning for cloud providers and virtualization platforms that rely heavily on this network device implementation. This issue particularly aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper integer handling leading to memory safety violations.
Mitigation strategies for CVE-2018-17958 should prioritize immediate patching of affected QEMU installations to the latest stable releases containing the corrected integer type handling. System administrators should also consider implementing network segmentation and access controls to limit exposure of virtualized environments to untrusted network traffic. Additional defensive measures include monitoring for anomalous network packet patterns that might indicate exploitation attempts, implementing network intrusion detection systems, and maintaining updated virtualization security policies. The vulnerability demonstrates the importance of rigorous input validation and type safety in virtualization components, aligning with ATT&CK technique T1055 for privilege escalation and T1082 for system information discovery. Organizations should also conduct thorough vulnerability assessments of their virtualization infrastructure to identify similar type-related issues in other emulated hardware components, as this class of vulnerability can manifest in various forms throughout complex virtualization environments.