CVE-2023-28320 : What You Need to Know

This CVE-2023-28320 involves a denial of service vulnerability found in curl <v8.1.0. The issue arises from the way libcurl offers various backends for resolving host names, which are chosen at build time. If configured to use the synchronous resolver, it permits name resolves to time-out slow operations using

alarm()

and

siglongjmp()

. Consequently, when utilizing this method, libcurl utilized a global buffer that lacked mutex protection, potentially causing crashes or other erratic behavior in multi-threaded applications.

Understanding CVE-2023-28320

This section delves into the specifics of CVE-2023-28320, shedding light on its nature, impact, technical details, and mitigation strategies.

What is CVE-2023-28320?

The CVE-2023-28320 vulnerability is classified under CWE-400 (Denial of Service) and affects versions of curl prior to 8.1.0. It exposes a flaw in the way libcurl handles host name resolutions when the synchronous resolver is enabled, leading to potential timeouts and instability in multi-threaded applications.

The Impact of CVE-2023-28320

The impact of CVE-2023-28320 can be severe, causing denial of service conditions in systems running affected versions of curl. Attackers could potentially exploit this vulnerability to disrupt services, crash applications, or trigger unexpected behavior in multi-threaded environments.

Technical Details of CVE-2023-28320

Delving deeper into the technical aspects of CVE-2023-28320 provides valuable insights into the vulnerability's description, affected systems, and exploitation mechanisms.

Vulnerability Description

The vulnerability in curl <v8.1.0 arises from the lack of mutex protection for a global buffer used during host name resolutions, specifically when employing the synchronous resolver. This flaw can be leveraged by attackers to trigger timeouts, leading to denial of service or application crashes in multi-threaded scenarios.

Affected Systems and Versions

The vulnerability impacts versions of curl prior to 8.1.0 that are built to use the synchronous resolver for host name resolutions. Systems running these versions are susceptible to the denial of service risk posed by CVE-2023-28320.

Exploitation Mechanism

By exploiting the lack of mutex protection in the global buffer utilized by libcurl during host name resolutions, malicious actors can induce slow operations using

alarm()

and

siglongjmp()

. This exploitation can result in crashes or erratic behavior in multi-threaded applications.

Mitigation and Prevention

Mitigating and preventing the risks associated with CVE-2023-28320 requires immediate action, adherence to security best practices, and timely application of patches and updates.

Immediate Steps to Take

To address CVE-2023-28320, users should prioritize updating curl to version 8.1.0 or above, where the vulnerability has been fixed. Additionally, reviewing and modifying the resolver configuration to ensure proper protection against denial of service attacks is recommended.

Long-Term Security Practices

In the long term, organizations are advised to implement robust security measures, conduct regular vulnerability assessments, and stay informed about potential threats and fixes in the software they use. Regular monitoring and updating of dependencies can help prevent similar vulnerabilities from being exploited.

Patching and Updates

Staying vigilant for security advisories and promptly applying patches and updates provided by software vendors is crucial to safeguarding systems against known vulnerabilities like CVE-2023-28320. Regularly monitoring vendor releases and community forums can help maintain a secure software environment.