CVE-2021-41160 : What You Need to Know

FreeRDP is a free implementation of the Remote Desktop Protocol (RDP) with an issue that could allow out of bound writes to memory in connected clients.

Understanding CVE-2021-41160

In this CVE, an improper region check in FreeRDP can lead to out of bound writes in connected clients.

What is CVE-2021-41160?

The vulnerability in FreeRDP allows a malicious server to trigger out of bound writes in a connected client, potentially compromising the client's memory.

The Impact of CVE-2021-41160

The vulnerability can result in out of bound writes in a connected client, particularly with connections using specific graphics updates, potentially leading to memory corruption.

Technical Details of CVE-2021-41160

FreeRDP versions prior to 2.4.1 are affected by this vulnerability.

Vulnerability Description

The issue arises when connections using GDI or SurfaceCommands to send graphics updates to the client might send

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width/height or out of bound rectangles, allowing out of bound writes.

Affected Systems and Versions

Vendor: FreeRDP
Product: FreeRDP
Affected Versions: < 2.4.1

Exploitation Mechanism

The vulnerability can be exploited when specific graphics updates are sent to the client, triggering out of bound writes in connected clients.

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent the exploitation of this vulnerability.

Immediate Steps to Take

Upgrade to FreeRDP version 2.4.1 or later to mitigate the vulnerability.
Monitor for any unusual or malicious activity on the network.

Long-Term Security Practices

Regularly update software and systems to ensure the latest security patches are in place.
Implement network segmentation and access controls to limit exposure to potential threats.

Patching and Updates

Ensure that all systems running FreeRDP are updated to version 2.4.1 or above to patch the vulnerability.