CVE-2020-15049 : Exploit Details and Defense Strategies

An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. This vulnerability allows for a Request Smuggling and Poisoning attack against the HTTP cache.

Understanding CVE-2020-15049

This CVE involves a security issue in Squid versions prior to 4.12 and 5.x before 5.0.3 that can be exploited for a Request Smuggling and Poisoning attack.

What is CVE-2020-15049?

CVE-2020-15049 is a vulnerability in Squid that enables attackers to conduct a Request Smuggling and Poisoning attack by manipulating the Content-Length header in an HTTP request.

The Impact of CVE-2020-15049

The impact of this CVE is rated as critical with a CVSS base score of 9.9. The attack can lead to high confidentiality, integrity, and availability impacts on affected systems.

Technical Details of CVE-2020-15049

This section provides more technical insights into the vulnerability.

Vulnerability Description

The vulnerability in Squid allows a client to send an HTTP request with a Content-Length header containing specific characters to manipulate the length field-value, enabling a Request Smuggling and Poisoning attack.

Affected Systems and Versions

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

Exploitation Mechanism

Attackers can exploit this vulnerability by sending HTTP requests with a Content-Length header containing certain characters that can manipulate the length field-value, leading to a successful Request Smuggling and Poisoning attack.

Mitigation and Prevention

To address CVE-2020-15049, follow these mitigation strategies:

Immediate Steps to Take

Update Squid to version 4.12 or 5.0.3, which contain fixes for this vulnerability.
Monitor and filter incoming HTTP requests for any suspicious Content-Length headers.

Long-Term Security Practices

Regularly update and patch software to the latest versions to prevent known vulnerabilities.
Implement network security measures to detect and block malicious HTTP requests.

Patching and Updates

Apply security patches provided by Squid promptly to ensure protection against CVE-2020-15049.