CVE-2019-11490 in Npcap
Summary
by MITRE
An issue was discovered in Npcap 0.992. Sending a malformed .pcap file with the loopback adapter using either pcap_sendqueue_queue() or pcap_sendqueue_transmit() results in kernel pool corruption. This could lead to arbitrary code executing inside the Windows kernel and allow escalation of privileges.
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Analysis
by VulDB Data Team • 09/06/2023
The vulnerability identified as CVE-2019-11490 represents a critical heap corruption flaw within the Npcap network capture library version 0.992. This issue specifically manifests when processing malformed .pcap files through the loopback adapter interface using the pcap_sendqueue_queue() or pcap_sendqueue_transmit() functions. The vulnerability resides in the kernel-mode driver component of Npcap, which handles packet transmission operations and operates with elevated privileges typically reserved for system-level processes. The flaw enables attackers to manipulate memory structures within the kernel pool, creating conditions that could result in arbitrary code execution with system-level privileges. This represents a severe privilege escalation vulnerability that directly impacts the security boundary between user-mode applications and kernel-mode drivers, as the affected functions are designed to handle packet transmission in network monitoring scenarios.
The technical exploitation of this vulnerability stems from insufficient input validation and memory management within the Npcap kernel driver. When the pcap_sendqueue_queue() or pcap_sendqueue_transmit() functions process malformed .pcap data, they fail to properly validate the structure and size of incoming packet data before attempting to queue or transmit it. This lack of proper bounds checking and memory allocation validation creates a condition where attacker-controlled data can overwrite kernel memory structures, leading to heap corruption. The vulnerability aligns with CWE-121, heap-based buffer overflow, and CWE-125, out-of-bounds read, as the flaw involves improper memory handling that allows for memory corruption in kernel space. The attack vector specifically targets the loopback adapter functionality, which is commonly used for network testing and monitoring, making it a frequent target for exploitation in security testing scenarios.
The operational impact of CVE-2019-11490 extends beyond simple privilege escalation to encompass complete system compromise. An attacker who successfully exploits this vulnerability can execute arbitrary code within kernel context, effectively bypassing standard user-mode security controls and access restrictions. This capability enables full system control, including the ability to install malware, modify system files, access sensitive data, and establish persistent backdoors. The vulnerability is particularly dangerous because it requires minimal privileges to exploit, as the functions involved are typically accessible to standard user accounts during normal network monitoring operations. The kernel pool corruption aspect means that the exploitation can potentially destabilize the operating system, leading to system crashes or hangs, while simultaneously providing a persistent execution environment for malicious payloads. This vulnerability directly maps to ATT&CK technique T1068, locally executed commands, and T1059, command and scripting interpreter, as it provides a mechanism for executing arbitrary code within the kernel.
Mitigation strategies for CVE-2019-11490 should focus on immediate patching of the Npcap library to version 0.993 or later, where the heap corruption issues have been addressed through improved input validation and memory management. System administrators should disable unnecessary network monitoring functions and restrict access to the pcap_sendqueue_queue() and pcap_sendqueue_transmit() functions where possible. Network security teams should implement monitoring for suspicious packet transmission patterns and malformed .pcap file processing, as these operations may indicate exploitation attempts. The vulnerability highlights the importance of kernel-mode driver security and proper input validation in security-critical software components. Organizations should also consider implementing application whitelisting policies to restrict which applications can access network capture functions, and establish regular vulnerability assessment procedures for network monitoring tools. Additionally, the use of automated network monitoring tools should be carefully reviewed to ensure they properly validate all input data before processing, particularly when dealing with packet capture files from untrusted sources. This vulnerability serves as a reminder of the critical security implications of kernel-mode vulnerabilities and the necessity of rigorous security testing for system-level components.