CVE-2019-11867 in NDIS Driver
Summary
by MITRE
Realtek NDIS driver rt640x64.sys, file version 10.1.505.2015, fails to do any size checking on an input buffer from user space, which the driver assumes has a size greater than zero bytes. To exploit this vulnerability, an attacker must send an IRP with a system buffer size of 0.
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Analysis
by VulDB Data Team • 03/30/2024
The vulnerability identified as CVE-2019-11867 affects the Realtek NDIS driver rt640x64.sys version 10.1.505.2015 which is part of the Windows operating system's network driver infrastructure. This driver implements network interface functionality for Realtek network adapters and operates at kernel level within the Windows kernel mode environment. The flaw manifests in the driver's insufficient validation of user-mode input buffers during IRP (I/O Request Packet) processing, creating a critical security gap that can be exploited by malicious actors. The vulnerability specifically targets the driver's handling of system buffer sizes, where it makes assumptions about buffer dimensions without proper validation checks. This type of vulnerability falls under the category of buffer overflow conditions that can lead to arbitrary code execution in kernel space, representing a severe threat to system integrity and security.
The technical implementation of this vulnerability stems from the driver's failure to validate input parameters during the processing of I/O requests. When an attacker crafts an IRP with a system buffer size of zero bytes, the driver's code path assumes that the buffer contains valid data and proceeds with operations that expect a non-zero buffer size. This assumption leads to memory access violations and potential exploitation opportunities. The vulnerability is classified as a buffer underflow or improper input validation issue, which aligns with CWE-129 and CWE-787 categories in the Common Weakness Enumeration catalog. The driver's lack of size checking creates a predictable exploitation vector that can be leveraged by attackers to execute malicious code with kernel privileges, effectively bypassing standard user-mode security controls.
The operational impact of this vulnerability extends beyond simple system instability to encompass complete system compromise and potential data breaches. Since the affected driver operates in kernel mode with elevated privileges, successful exploitation can result in complete system control, allowing attackers to install malware, modify system files, or extract sensitive information from memory. The vulnerability is particularly concerning because it requires minimal privileges to exploit and can be triggered through legitimate I/O operations that network drivers typically process. This characteristic makes it suitable for both local and remote exploitation scenarios, potentially enabling attackers to perform privilege escalation attacks or establish persistent backdoors within target systems. The attack surface is broad as any application or service that interacts with the network adapter through this driver can potentially serve as an attack vector.
Mitigation strategies for CVE-2019-11867 should focus on immediate patching of the affected Realtek driver components, as Microsoft has released security updates to address this specific vulnerability. Organizations should prioritize deployment of the latest Realtek driver versions that include proper buffer validation mechanisms and size checking procedures. Network administrators should also implement monitoring solutions to detect anomalous IRP processing patterns that might indicate exploitation attempts. The vulnerability's characteristics align with ATT&CK technique T1068 which involves exploiting vulnerabilities in legitimate programs, and T1059 which covers command and scripting interpreter usage. System hardening measures including kernel mode driver validation, runtime application control, and regular security assessments can help reduce the risk of exploitation. Additionally, implementing network segmentation and access controls can limit the potential damage if exploitation occurs, while regular vulnerability scanning and penetration testing should be conducted to identify similar issues in other system components.