CVE-2023-39356 Explained : Impact and Mitigation

A missing offset validation in FreeRDP has led to an Out-of-Bounds Read vulnerability, impacting certain versions.

Understanding CVE-2023-39356

This CVE involves a flaw in FreeRDP that can result in an Out-of-Bounds Read due to missing offset validation.

What is CVE-2023-39356?

FreeRDP, a Remote Desktop Protocol (RDP) implementation under the Apache license, is affected by a vulnerability in the function

gdi_multi_opaque_rect

where inadequate validation of

numRectangles

value can lead to Out-of-Bounds Read errors, potentially causing a crash.

The Impact of CVE-2023-39356

The vulnerability can be exploited in affected versions of FreeRDP, potentially resulting in unauthorized access or denial of service.

Technical Details of CVE-2023-39356

This section details the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The vulnerability arises from the lack of proper boundary checks while iterating through

numRectangles

in the function

gdi_multi_opaque_rect

.

Affected Systems and Versions

Versions prior to 2.11.0 and between 3.0.0-beta1 and 3.0.0-beta3 of FreeRDP are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by triggering the Out-of-Bounds Read error through specific input to the affected function.

Mitigation and Prevention

To mitigate the risks associated with CVE-2023-39356, users are advised to take immediate steps and adopt long-term security practices.

Immediate Steps to Take

Upgrade FreeRDP to versions 2.11.0 or 3.0.0-beta3, as these versions contain fixes for the vulnerability.

Long-Term Security Practices

Regularly update software, implement strong access controls, and monitor for any suspicious activities to enhance overall cybersecurity posture.

Patching and Updates

Stay informed about security advisories and apply patches promptly to protect systems from potential threats.