CVE-2021-28652 : Vulnerability Insights and Analysis

A Denial of Service vulnerability was discovered in Squid versions before 4.15 and 5.x before 5.0.6, allowing a trusted client to trigger memory leaks via an incorrect parser validation in the Cache Manager API.

Understanding CVE-2021-28652

This CVE involves a vulnerability in the Squid caching proxy software that can be exploited by a trusted client with Cache Manager API access privilege to cause a Denial of Service attack through memory leaks.

What is CVE-2021-28652?

The issue in Squid versions before 4.15 and 5.x before 5.0.6 enables a trusted client to exploit incorrect parser validation, leading to memory leaks that ultimately result in a Denial of Service through a short query string.

The Impact of CVE-2021-28652

Exploitation of this vulnerability can result in a Denial of Service condition, affecting the availability of the Cache Manager API and potentially disrupting the functioning of the Squid caching proxy service.

Technical Details of CVE-2021-28652

This section outlines specific technical details related to the CVE.

Vulnerability Description

The vulnerability stems from incorrect parser validation in Squid software, allowing trusted clients to exploit the Cache Manager API and trigger memory leaks, resulting in a potential Denial of Service attack.

Affected Systems and Versions

All Squid versions before 4.15 and 5.x before 5.0.6 are affected by this vulnerability.

Exploitation Mechanism

Exploiting this vulnerability requires a trusted client with Cache Manager API access privilege to send a specific short query string, leading to memory leaks over time and a subsequent Denial of Service.

Mitigation and Prevention

To address and prevent the exploitation of CVE-2021-28652, the following immediate steps and long-term security practices are recommended.

Immediate Steps to Take

Update Squid to version 4.15 or 5.0.6, which includes a patch to correct the parser validation issue.
Restrict access to the Cache Manager API to trusted entities only.

Long-Term Security Practices

Regularly monitor and apply security updates and patches for Squid software.
Implement network segmentation to limit the impact of potential Denial of Service attacks.

Patching and Updates

Refer to the provided vendor advisories and security updates mentioned in the references to apply the necessary patches and updates to mitigate the CVE-2021-28652 vulnerability.