CVE-2021-41159 : Exploit Details and Defense Strategies

CVE-2021-41159 relates to an improper input validation vulnerability in FreeRDP that could lead to memory overwrite when using gateway connections. The issue affects versions prior to 2.4.1.

Understanding CVE-2021-41159

CVE-2021-41159 is a security vulnerability in FreeRDP that allows malicious gateways to write client memory out of bounds. It has been resolved in version 2.4.1.

What is CVE-2021-41159?

The vulnerability in FreeRDP arises from the failure to validate input data for gateway connections, potentially leading to memory corruption.

The Impact of CVE-2021-41159

This vulnerability could be exploited by a malicious gateway to overwrite client memory, posing a risk to the integrity of the system.

Technical Details of CVE-2021-41159

FreeRDP versions prior to 2.4.1 are susceptible to this vulnerability.

Vulnerability Description

The issue stems from improper client input validation for FreeRDP gateway connections, allowing memory overwrite.

Affected Systems and Versions

Vendor: FreeRDP
Product: FreeRDP
Vulnerable Versions: < 2.4.1

Exploitation Mechanism

Attack Vector: Network
Attack Complexity: High
Privileges Required: High
User Interaction: None
Scope: Changed
Confidentiality Impact: None
Integrity Impact: High
Availability Impact: None
CVSS Base Score: 5.8 (Medium)

Mitigation and Prevention

To address CVE-2021-41159, follow these steps:

Immediate Steps to Take

Update FreeRDP to version 2.4.1 or newer.
If unable to update, consider using

/gt:http

instead of

/gt:rpc

connections.
Prefer direct connections without a gateway whenever possible.

Long-Term Security Practices

Regularly update software to the latest versions.
Conduct security assessments to identify and mitigate vulnerabilities.

Patching and Updates

Ensure timely patching of FreeRDP to the latest version to prevent exploitation of this vulnerability.