CVE-2023-27371 Explained : Impact and Mitigation

This CVE record pertains to a vulnerability in GNU libmicrohttpd before version 0.9.76 that allows for a remote Denial of Service (DoS) attack. The issue arises from improper parsing of a multipart/form-data boundary in the postprocessor.c MHD_create_post_processor() method. An attacker could exploit this vulnerability by sending a malicious HTTP POST packet containing one or more '\0' bytes in a multipart/form-data boundary field, leading to an out-of-bounds read and a crash in the find_boundary() function.

Understanding CVE-2023-27371

This section delves into the details of CVE-2023-27371, exploring what the vulnerability entails and its potential impact.

What is CVE-2023-27371?

CVE-2023-27371 is a vulnerability in GNU libmicrohttpd before version 0.9.76 that enables a remote DoS attack due to improper parsing of a multipart/form-data boundary in the postprocessor.c MHD_create_post_processor() method.

The Impact of CVE-2023-27371

The impact of CVE-2023-27371 is significant as it allows attackers to remotely trigger a DoS condition on systems running the affected versions of GNU libmicrohttpd.

Technical Details of CVE-2023-27371

In this section, we will explore the technical aspects of CVE-2023-27371, including vulnerability description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The vulnerability in GNU libmicrohttpd before 0.9.76 stems from the improper handling of a multipart/form-data boundary, leading to an out-of-bounds read and subsequent crash in the find_boundary() function.

Affected Systems and Versions

The vulnerability impacts GNU libmicrohttpd versions before 0.9.76. The exact vendor and product details are not available.

Exploitation Mechanism

An attacker can exploit CVE-2023-27371 by crafting a malicious HTTP POST packet containing '\0' bytes in a multipart/form-data boundary field, leveraging a specific heap layout to trigger the out-of-bounds read.

Mitigation and Prevention

To address CVE-2023-27371 and mitigate the risks associated with this vulnerability, it is crucial to take immediate steps, adopt long-term security practices, and ensure timely patching and updates.

Immediate Steps to Take

Organizations should consider updating GNU libmicrohttpd to version 0.9.76 or later to mitigate the vulnerability.
Employ network-level protections to detect and block potential malicious HTTP POST packets targeting this vulnerability.

Long-Term Security Practices

Implement secure coding practices, conduct regular security assessments, and stay informed about the latest vulnerabilities and patches to proactively defend against similar threats.

Patching and Updates

Stay informed about security advisories and updates released by GNU libmicrohttpd to promptly apply patches that address CVE-2023-27371 and other potential vulnerabilities.