CVE-2023-47120 : What You Need to Know

Discourse DoS through Onebox favicon URL is a high-severity vulnerability impacting Discourse platforms.

Understanding CVE-2023-47120

This CVE involves a Denial of Service (DoS) vulnerability in Discourse platforms due to an issue related to the favicon URL processing.

What is CVE-2023-47120?

Discourse, an open-source platform for community discussion, is affected by a vulnerability in versions 3.1.0 to 3.1.2 of the stable branch and versions 3.1.0.beta6 to 3.2.0.beta2 of the beta and tests-passed branches. The vulnerability allows attackers to deplete Redis memory by creating a site with an excessively long favicon URL and posting multiple Onebox references to it. The issue has been addressed in versions 3.1.3 and 3.2.0.beta3 of the respective branches, with no known workarounds.

The Impact of CVE-2023-47120

The impact of this vulnerability is rated as high (CVSS base score: 7.5). It poses a significant threat to the availability of Discourse platforms, potentially leading to service disruptions and denial of access to legitimate users.

Technical Details of CVE-2023-47120

This section provides detailed technical insights into the vulnerability.

Vulnerability Description

The vulnerability arises from the improper handling of favicon URLs, allowing malicious actors to exhaust Redis memory resources through crafted requests, leading to a DoS condition.

Affected Systems and Versions

Versions 3.1.0 to 3.1.2 of the stable branch and versions 3.1.0.beta6 to 3.2.0.beta2 of the beta and tests-passed branches are affected by this CVE.

Exploitation Mechanism

Attackers can exploit this vulnerability by creating a site with an oversized favicon URL and generating multiple posts that Onebox it, causing excessive resource consumption.

Mitigation and Prevention

Discover how to address and prevent the CVE-2023-47120 vulnerability.

Immediate Steps to Take

Users are advised to update their Discourse installations to the patched versions (3.1.3 and 3.2.0.beta3) immediately to mitigate the risk of exploitation.

Long-Term Security Practices

Implementing proper input validation mechanisms, monitoring memory usage, and promptly applying software updates can help prevent similar vulnerabilities in the future.

Patching and Updates

Regularly check for security updates and apply patches as soon as they are available to keep Discourse platforms secure from known vulnerabilities.