CVE-2023-30587 is a high-severity vulnerability affecting Node.js, specifically impacting the experimental permission model feature available in Node.js version 20 and earlier versions listed (4.0 through 20.0). The vulnerability arises from a flaw in the interaction between the Worker class and the built-in inspector module (node:inspector). The Worker class can create an "internal worker" by leveraging the kIsInternal Symbol. An attacker can exploit this by modifying the isInternal property when an inspector is attached within the Worker constructor, prior to initializing a new WorkerImpl instance. This manipulation allows bypassing the restrictions imposed by the --experimental-permission flag, effectively circumventing the permission model's security controls. The permission model in Node.js is designed to restrict certain operations or capabilities to enhance security, but since it is experimental, it may not have full maturity or hardened defenses. The vulnerability does not require authentication or user interaction and can be exploited remotely (AV:N), with low attack complexity (AC:L). The impact is primarily on integrity (I:H), allowing an attacker to perform unauthorized actions or escalate privileges within the Node.js environment, though confidentiality and availability are not directly impacted. There are no known exploits in the wild at the time of publication, and no official patches have been linked yet. The vulnerability is classified under CWE-284 (Improper Access Control), indicating a failure to enforce intended restrictions properly.

For European organizations, this vulnerability poses a significant risk, especially for those relying on Node.js applications that utilize the experimental permission model or the inspector module. The ability to bypass permission restrictions can lead to unauthorized code execution or privilege escalation within server-side applications, potentially compromising application integrity and trustworthiness. This could result in unauthorized modifications to application logic, data tampering, or further lateral movement within internal networks. Organizations in sectors such as finance, healthcare, and critical infrastructure, which often deploy Node.js for backend services, could face increased risk of targeted attacks exploiting this flaw. Additionally, since the vulnerability does not require authentication or user interaction, automated exploitation attempts could be feasible, increasing the threat surface. The lack of a patch at the time of disclosure means organizations must rely on mitigations or configuration changes to reduce risk. Given the experimental nature of the permission model, many production environments may not yet use this feature extensively, potentially limiting immediate impact, but early adopters or development environments could be vulnerable.

1. Disable the experimental permission model feature until a patch is available or the feature is deemed stable and secure. Avoid using the --experimental-permission flag in production environments. 2. Restrict or disable the use of the node:inspector module in production deployments, as it is a key component exploited in this vulnerability. 3. Implement strict runtime environment controls and sandboxing to limit the impact of any potential exploitation, including containerization and least privilege principles. 4. Monitor Node.js application logs and network traffic for unusual activity related to worker creation or inspector attachment. 5. Stay updated with Node.js security advisories and apply patches promptly once released. 6. Conduct code reviews and security assessments focusing on the usage of Workers and permission models in Node.js applications. 7. Consider employing Web Application Firewalls (WAFs) or runtime application self-protection (RASP) tools that can detect and block suspicious behaviors related to this vulnerability.