CVE-2020-9332 in USB for Remote Desktop
Summary
by MITRE
ftusbbus2.sys in FabulaTech USB for Remote Desktop through 2020-02-19 allows privilege escalation via crafted IoCtl code related to a USB HID device.
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Analysis
by VulDB Data Team • 06/18/2020
The vulnerability identified as CVE-2020-9332 affects the ftusbbus2.sys driver component within FabulaTech USB for Remote Desktop software version 2020-02-19 and earlier. This driver operates at the kernel level and serves as an intermediary for USB HID device communication within remote desktop sessions. The flaw manifests through improper validation of IOCTL (Input/Output Control) codes that are processed when handling USB HID device interactions. The vulnerability specifically arises from the driver's failure to properly validate or sanitize IOCTL requests that are directed to USB HID devices, creating an opportunity for malicious code execution at elevated privileges.
The technical implementation of this vulnerability stems from a lack of input validation within the driver's IOCTL handling mechanism. When a USB HID device is connected through the FabulaTech USB for Remote Desktop system, the ftusbbus2.sys driver receives various IOCTL commands to manage device operations. The driver processes these commands without adequate verification of the command codes or associated parameters, allowing an attacker to submit crafted IOCTL requests that can manipulate the driver's behavior. This improper validation creates a privilege escalation path where unprivileged users can potentially execute arbitrary code with kernel-level privileges, effectively bypassing standard operating system security boundaries.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it represents a critical security weakness that can be exploited by attackers to gain complete system control. Attackers can leverage this vulnerability to execute malicious code with SYSTEM-level privileges, potentially leading to full system compromise, data exfiltration, or persistent backdoor installation. The vulnerability affects systems where FabulaTech USB for Remote Desktop is installed, particularly in enterprise environments where remote desktop functionality is commonly deployed. The elevated privilege level achieved through this exploit allows attackers to bypass standard security controls, including user access controls, application whitelisting, and other endpoint protection mechanisms.
Mitigation strategies for CVE-2020-9332 should focus on immediate software updates from FabulaTech, as the vendor has released patches to address this specific vulnerability. Organizations should implement comprehensive vulnerability management processes to identify systems running affected versions of the software and apply patches promptly. Network segmentation and access controls should be strengthened to limit potential attack vectors, while monitoring systems should be configured to detect anomalous IOCTL activity patterns that might indicate exploitation attempts. Security teams should also consider implementing kernel-mode exploit detection mechanisms and maintaining up-to-date threat intelligence feeds that specifically address vulnerabilities in USB device drivers. This vulnerability aligns with CWE-119, which addresses "Improper Restriction of Operations within the Bounds of a Memory Buffer," and represents a typical example of how kernel-mode driver vulnerabilities can be exploited to achieve privilege escalation as documented in ATT&CK technique T1068, "Exploitation for Privilege Escalation."