CVE-2020-14058 : Security Advisory and Response

An issue was discovered in Squid before 4.12 and 5.x before 5.0.3, making them vulnerable to a Denial of Service attack when establishing a TLS connection to a malicious server.

Understanding CVE-2020-14058

This CVE identifies a vulnerability in Squid versions prior to 4.12 and 5.x before 5.0.3 that could lead to a Denial of Service (DoS) attack.

What is CVE-2020-14058?

The vulnerability in Squid arises from the use of a potentially dangerous function that can be exploited to trigger a DoS attack by opening a TLS connection to a server controlled by an attacker.

The Impact of CVE-2020-14058

The vulnerability allows an attacker to cause a DoS condition by manipulating error values, leading to service disruption and potential system unavailability.

Technical Details of CVE-2020-14058

Squid versions before 4.12 and 5.x before 5.0.3 are affected by this vulnerability.

Vulnerability Description

The issue stems from the incorrect handling of error values, which can result in a NULL mapping, contrary to the expected valid error string mapping.

Affected Systems and Versions

Product: Squid
Vendor: N/A
Versions: Squid versions before 4.12 and 5.x before 5.0.3

Exploitation Mechanism

Attackers can exploit this vulnerability by establishing a TLS connection to a server they control, manipulating error values to trigger a DoS condition.

Mitigation and Prevention

To address CVE-2020-14058, follow these steps:

Immediate Steps to Take

Update Squid to version 4.12 or 5.0.3, which contain fixes for this vulnerability.
Monitor network traffic for any suspicious activity that could indicate exploitation.

Long-Term Security Practices

Regularly update and patch software to mitigate known vulnerabilities.
Implement network segmentation and access controls to limit the impact of potential attacks.

Patching and Updates

Apply patches provided by Squid to address the vulnerability and enhance system security.