CVE-2018-20178 : Security Advisory and Response

rdesktop versions up to and including v1.8.3 contain an Out-Of-Bounds Read vulnerability in the function process_demand_active(), leading to a Denial of Service (DoS) in the form of a segfault.

Understanding CVE-2018-20178

What is CVE-2018-20178?

CVE-2018-20178 is a vulnerability found in rdesktop versions 1.8.3 and below, where an Out-Of-Bounds Read occurs in the process_demand_active() function, resulting in a DoS by causing a segfault.

The Impact of CVE-2018-20178

The vulnerability allows attackers to trigger a DoS condition, potentially disrupting the availability of the affected system or service.

Technical Details of CVE-2018-20178

Vulnerability Description

The vulnerability in rdesktop versions up to v1.8.3 stems from an Out-Of-Bounds Read issue in the process_demand_active() function, leading to a DoS through a segfault.

Affected Systems and Versions

Product: rdesktop
Vendor: N/A
Versions affected: 1.8.3 and below

Exploitation Mechanism

The vulnerability can be exploited by sending specially crafted input to the vulnerable function, triggering the Out-Of-Bounds Read and causing the Denial of Service.

Mitigation and Prevention

Immediate Steps to Take

Apply the latest security patches provided by the vendor.
Consider implementing network-level protections to filter out malicious traffic targeting the vulnerable component.

Long-Term Security Practices

Regularly update and patch software to mitigate known vulnerabilities.
Conduct security assessments and audits to identify and address potential weaknesses in the system.

Patching and Updates

It is crucial to update rdesktop to a version that includes a fix for CVE-2018-20178 to prevent exploitation of the vulnerability.