CVE-2023-29323 : Security Advisory and Response

OpenBSD and OpenSMTPD Vulnerability

Understanding CVE-2023-29323

This CVE refers to the

ascii_load_sockaddr

function in

smtpd

in OpenBSD before 7.1 errata 024 and 7.2 before errata 020, and OpenSMTPD Portable before 7.0.0-portable commit f748277, which can abort upon a connection from a local scoped IPv6 address.

What is CVE-2023-29323?

CVE-2023-29323 describes a vulnerability in OpenBSD's

smtpd

and OpenSMTPD Portable versions that allows an attack via a local, scoped IPv6 address, potentially leading to an abort of the service.

The Impact of CVE-2023-29323

Exploitation of this vulnerability could result in a denial of service (DoS) condition, disrupting the availability of the affected services and systems.

Technical Details of CVE-2023-29323

Vulnerability Description

The vulnerability lies in the

ascii_load_sockaddr

function within

smtpd

, which fails to handle local, scoped IPv6 addresses properly, triggering an erroneous service abort.

Affected Systems and Versions

All versions of OpenBSD before 7.1 errata 024 and 7.2 before errata 020, as well as OpenSMTPD Portable before 7.0.0-portable commit f748277, are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by establishing a connection using a local, scoped IPv6 address, triggering the service to halt unexpectedly.

Mitigation and Prevention

Immediate Steps to Take

To mitigate the risk associated with CVE-2023-29323, affected users are advised to update OpenBSD to version 7.1 errata 024 or version 7.2 errata 020, and OpenSMTPD Portable to version 7.0.0-portable commit f748277.

Long-Term Security Practices

Maintaining up-to-date software versions and applying security patches promptly is crucial in safeguarding systems against known vulnerabilities.

Patching and Updates

Regularly check for security advisories and updates from OpenBSD and OpenSMTPD to stay informed about the latest patches and security enhancements.