CVE-2019-19536 in Linux
Summary
by MITRE
In the Linux kernel before 5.2.9, there is an info-leak bug that can be caused by a malicious USB device in the drivers/net/can/usb/peak_usb/pcan_usb_pro.c driver, aka CID-ead16e53c2f0.
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Analysis
by VulDB Data Team • 03/07/2024
The vulnerability identified as CVE-2019-19536 represents a critical information disclosure flaw within the Linux kernel's CAN (Controller Area Network) USB driver implementation. This issue specifically affects systems running Linux kernel versions prior to 5.2.9 and manifests through the peak_usb driver component located in the drivers/net/can/usb/peak_usb/pcan_usb_pro.c file. The vulnerability arises from improper handling of data structures during USB device communication, creating a pathway for unauthorized information exposure. The attack vector involves a maliciously crafted USB device that can trigger the information leak when connected to a vulnerable system, making this a particularly concerning flaw given the widespread use of USB interfaces in modern computing environments.
The technical root cause of this vulnerability stems from insufficient validation and proper memory management within the USB communication handling routines of the CAN driver. When a USB device connects and communicates with the system through the peak_usb driver, specific data structures containing sensitive information are not properly sanitized or cleared before being exposed to userspace. This allows an attacker with physical access to a vulnerable system to potentially extract kernel memory contents, including potentially sensitive data such as cryptographic keys, passwords, or other confidential information stored in memory. The vulnerability is classified as an information disclosure issue under CWE-200, which specifically addresses the exposure of sensitive information to unauthorized actors. The flaw demonstrates poor input validation and memory handling practices that violate fundamental security principles for kernel space operations.
The operational impact of CVE-2019-19536 extends beyond simple information disclosure, as it creates potential pathways for more sophisticated attacks. An attacker with physical access to a vulnerable system could leverage this information leak to gain insights into the kernel memory layout, potentially enabling further exploitation techniques such as bypassing kernel address space layout randomization (ASLR) or discovering memory corruption vulnerabilities. The attack requires physical access to the target system, which aligns with the ATT&CK framework's privilege escalation techniques where adversaries gain access through physical presence. Systems using automotive, industrial control, or embedded computing environments that rely heavily on USB CAN interfaces are particularly at risk, as these environments often operate in environments where physical security is challenging to maintain.
Mitigation strategies for this vulnerability center on kernel version updates and proper system hardening measures. The primary and most effective solution involves upgrading to Linux kernel version 5.2.9 or later, where the information leak has been addressed through proper memory handling and data structure validation. System administrators should also implement USB device access controls and monitoring to detect unauthorized USB device connections. Additional protective measures include enabling kernel lockdown modes, implementing USB device whitelisting policies, and conducting regular security assessments of USB interfaces. Organizations should consider implementing physical security controls to prevent unauthorized USB device insertion, particularly in high-security environments. The vulnerability also underscores the importance of regular kernel security updates and maintaining current system patches to protect against known information disclosure vulnerabilities. Security teams should monitor for similar patterns in other USB driver implementations and ensure comprehensive testing of device drivers to prevent similar memory exposure issues in other kernel subsystems.