CVE-2020-17382: MSI AmbientLink Buffer Overflow Flaw

CVE-2020-17382 Overview

CVE-2020-17382 is a buffer overflow vulnerability affecting the MSI AmbientLink MsIo64 driver version 1.0.0.8. The vulnerability exists in multiple IOCTL handlers (0x80102040, 0x80102044, 0x80102050, and 0x80102054) and can be exploited by a local attacker to achieve privilege escalation on affected Windows systems. This is classified as an out-of-bounds write vulnerability (CWE-787) that allows attackers with low privileges to potentially gain complete control over the affected system.

Critical Impact

Local attackers with low privileges can exploit this buffer overflow to achieve privilege escalation, potentially gaining SYSTEM-level access on Windows machines running the vulnerable MSI driver.

Affected Products

• MSI AmbientLink MsIo64 Firmware version 1.0.0.8
• MSI AmbientLink MsIo64 Hardware Device
• Systems with MSI graphics card software utilizing the vulnerable driver

Discovery Timeline

• 2020-10-02 - CVE-2020-17382 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-17382

Vulnerability Analysis

The MSI AmbientLink MsIo64 driver contains multiple buffer overflow vulnerabilities in its IOCTL (Input/Output Control) handling routines. The affected IOCTL codes are 0x80102040, 0x80102044, 0x80102050, and 0x80102054. When processing user-supplied input through these IOCTL handlers, the driver fails to properly validate buffer boundaries, leading to out-of-bounds write conditions.

As a kernel-mode driver vulnerability, successful exploitation allows attackers to execute arbitrary code with kernel privileges. The local attack vector requires an attacker to already have access to the system, but only low-level privileges are needed to trigger the vulnerability. No user interaction is required for exploitation.

Root Cause

The root cause of this vulnerability is improper input validation in the driver's IOCTL handlers. The MsIo64.sys driver does not adequately verify the size or content of buffers passed through DeviceIoControl calls. This allows a malicious local application to send specially crafted IOCTL requests that overflow internal driver buffers, corrupting kernel memory and potentially allowing arbitrary code execution in kernel mode.

Attack Vector

The attack vector is local, requiring the attacker to execute malicious code on the target system. An attacker can exploit this vulnerability by:

1. Opening a handle to the vulnerable MsIo64 device driver
2. Crafting a malicious IOCTL request targeting one of the vulnerable handlers
3. Sending the crafted request via the DeviceIoControl API
4. Triggering the buffer overflow to corrupt kernel memory
5. Leveraging the memory corruption for privilege escalation

The vulnerability can be exploited through any of the four vulnerable IOCTL codes. Technical details and proof-of-concept information are available in the Core Security MSI Ambient Link Advisory and the Packet Storm Privilege Escalation Advisory.

Detection Methods for CVE-2020-17382

Indicators of Compromise

• Presence of MsIo64.sys driver version 1.0.0.8 on the system
• Suspicious processes attempting to open handles to \\.\MsIo64 device
• Unexpected SYSTEM-level process spawning from low-privileged applications
• Kernel crash dumps indicating memory corruption in MsIo64.sys

Detection Strategies

• Monitor for processes making DeviceIoControl calls to the MsIo64 driver device
• Implement driver blocklist policies to prevent loading of the vulnerable driver version
• Use endpoint detection and response (EDR) solutions to detect kernel exploitation attempts
• Enable Windows Driver Signature Enforcement to prevent unsigned driver loading

Monitoring Recommendations

• Configure Security Information and Event Management (SIEM) to alert on driver load events for MsIo64.sys
• Monitor for privilege escalation indicators such as token manipulation or unexpected admin processes
• Implement application whitelisting to restrict which applications can interact with hardware drivers
• Review system event logs for unusual driver-related errors or crashes

How to Mitigate CVE-2020-17382

Immediate Actions Required

• Update the MSI AmbientLink driver to a patched version from the official MSI support portal
• Remove or disable the vulnerable MsIo64.sys driver if not required for system functionality
• Implement the Windows Defender Application Control (WDAC) driver blocklist
• Restrict local access to only trusted users and applications

Patch Information

MSI has released updated drivers to address this vulnerability. Users should visit the MSI VGA Driver Download Page to obtain the latest driver version. Ensure that the updated driver version is higher than 1.0.0.8 and verify the digital signature before installation.

Workarounds

• Unload and block the vulnerable driver using Device Manager or driver management tools
• Use Windows Security policies to block known vulnerable drivers via the Microsoft recommended driver block rules
• Implement application control policies to prevent untrusted applications from interacting with system drivers
• Monitor for and alert on any attempts to load the vulnerable driver version

# Block vulnerable driver using Windows Defender Application Control
# Add MsIo64.sys version 1.0.0.8 to driver blocklist policy
# Example using Group Policy or Intune to deploy WDAC policy

# Manually disable the driver (requires administrator privileges)
sc stop MsIo64
sc config MsIo64 start= disabled

# Verify driver status
sc query MsIo64