CVE-2023-3384 is a vulnerability classified as an improper neutralization of input during web page generation, specifically a cross-site scripting (XSS) flaw in Red Hat Quay 3, a popular container image registry solution. The vulnerability stems from inconsistent input validation: while image labels created through the Quay UI and backend are validated using a regex pattern (validation.py), labels originating directly from container images bypass this validation. This discrepancy allows an attacker to embed malicious JavaScript code within image labels. When such a malicious image is published to a public registry and viewed through the Quay web interface, the embedded script executes in the context of the user's browser, leading to an XSS attack. The CVSS v3.1 base score is 5.4 (medium severity), with an attack vector of network (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), and user interaction (UI:R). The scope is changed (S:C), meaning the vulnerability affects components beyond the initially vulnerable component. The impact affects confidentiality and integrity partially (C:L, I:L), but not availability (A:N). No known exploits are reported in the wild, but the vulnerability could be leveraged to steal session tokens, perform actions on behalf of users, or conduct phishing attacks within the registry's web interface. This vulnerability is particularly concerning for organizations that host public or semi-public container registries using Red Hat Quay 3, as attackers can upload malicious images that trigger XSS when viewed by other users. The flaw highlights the importance of consistent input validation across all data sources, especially in web applications handling user-generated content or third-party inputs.

For European organizations, the impact of CVE-2023-3384 can be significant, especially for those relying on Red Hat Quay 3 for container image management. Successful exploitation could lead to the execution of arbitrary scripts in the context of legitimate users accessing the registry, potentially exposing session cookies, authentication tokens, or other sensitive information. This can facilitate unauthorized actions such as privilege escalation, data leakage, or manipulation of container images metadata. Given the increasing adoption of containerization and DevOps practices in Europe, organizations using public or internal registries without strict access controls are at risk. The vulnerability could also undermine trust in container supply chains if malicious images are distributed. While the vulnerability does not directly impact system availability, the compromise of confidentiality and integrity can lead to broader security incidents, including lateral movement within networks or compromise of deployment pipelines. Additionally, regulatory frameworks such as GDPR impose strict data protection requirements, and exploitation leading to data breaches could result in legal and financial penalties. Organizations in sectors with high container usage—such as finance, telecommunications, and technology—may face elevated risks due to the criticality of their infrastructure and data.

To mitigate CVE-2023-3384, European organizations should implement the following specific measures: 1) Apply all available patches or updates from Red Hat for Quay 3 as soon as they are released to ensure the regex validation is consistently applied to all image labels, including those originating from images. 2) Enforce strict input validation and sanitization on all user-supplied data and metadata, including image labels, at all entry points within the registry. 3) Restrict public access to container registries where possible, limiting image uploads and views to authenticated and authorized users only, thereby reducing exposure to malicious uploads. 4) Implement Content Security Policy (CSP) headers in the Quay web interface to limit the execution of unauthorized scripts and reduce the impact of potential XSS attacks. 5) Monitor registry logs and image metadata for unusual or suspicious label content that may indicate exploitation attempts. 6) Educate developers and DevOps teams about secure image labeling practices and the risks of unvalidated metadata. 7) Consider deploying web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting the registry interface. 8) Regularly audit container images and metadata for compliance with security policies before deployment. These targeted actions go beyond generic advice by focusing on the specific vectors and context of this vulnerability.