CVE-2024-30050 is a medium-severity vulnerability affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability is categorized under CWE-693, which relates to Protection Mechanism Failure. Specifically, this issue involves a bypass of the Windows Mark of the Web (MotW) security feature. MotW is designed to mark files downloaded from the internet with a security zone identifier, which Windows and associated applications use to enforce security policies such as warning prompts or restricted execution to mitigate risks from untrusted content. The bypass vulnerability means that an attacker could craft files or content that evade these MotW checks, potentially allowing malicious code or scripts to execute with fewer restrictions than intended. According to the CVSS 3.1 vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L/E:F/RL:O/RC:C), the vulnerability can be exploited remotely over the network without privileges and requires user interaction (UI:R). The impact affects integrity and availability but not confidentiality. The exploitability is functional (E:F), and the vulnerability is officially confirmed (RC:C) with an overall CVSS score of 5.4, classified as medium severity. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability could allow an attacker to bypass security prompts or restrictions, potentially leading to limited integrity and availability impacts such as unauthorized modification or disruption of system or application behavior. However, exploitation requires user interaction, such as opening a malicious file or link, limiting the attack vector scope. This vulnerability primarily affects legacy systems still running Windows 10 Version 1809, which is an older release with extended support but no longer the latest Windows 10 or Windows 11 versions. Organizations running this version are at risk if they have not applied mitigations or upgrades.

For European organizations, the impact of CVE-2024-30050 is moderate but non-negligible. Many enterprises, especially in sectors with strict compliance requirements or legacy application dependencies, may still operate Windows 10 Version 1809 systems. The MotW bypass could enable attackers to deliver malicious payloads that evade security warnings, increasing the risk of malware infections or unauthorized script execution. This could lead to integrity issues such as unauthorized changes to system files or application configurations and availability issues like service disruptions or application crashes. Confidential data leakage is not directly implicated by this vulnerability. The requirement for user interaction reduces the likelihood of large-scale automated exploitation but does not eliminate targeted phishing or social engineering attacks. European organizations with extensive remote workforces or those relying on email and web downloads as vectors could be more vulnerable. Additionally, sectors such as finance, healthcare, and critical infrastructure that maintain legacy Windows 10 deployments may face increased risk. The absence of known exploits in the wild currently limits immediate threat levels, but the presence of a functional exploit vector means proactive mitigation is essential to prevent future attacks.

1. Upgrade and Patch: The most effective mitigation is to upgrade affected systems from Windows 10 Version 1809 to a more recent, supported Windows version (e.g., Windows 10 21H2 or Windows 11) where this vulnerability is not present or has been patched. If upgrading is not immediately feasible, monitor Microsoft security advisories for patches addressing CVE-2024-30050 and apply them promptly once available. 2. User Awareness and Training: Since exploitation requires user interaction, enhance user training to recognize suspicious files, links, and social engineering attempts. Emphasize caution when opening files from untrusted sources or unexpected email attachments. 3. Application Whitelisting and Execution Controls: Implement application control policies that restrict execution of untrusted or unsigned code, especially from internet zones. Use Windows Defender Application Control (WDAC) or AppLocker to enforce strict execution policies. 4. Network Segmentation and Least Privilege: Limit network access and user privileges to reduce the impact scope if exploitation occurs. Restrict internet-facing services and isolate legacy systems to minimize exposure. 5. Enhanced Email and Web Filtering: Deploy advanced email security solutions that scan and block malicious attachments or links that could exploit MotW bypass. Similarly, use web proxies or secure web gateways to filter downloads and prevent access to malicious sites. 6. Monitor and Audit: Enable logging and monitoring for unusual file execution or system behavior on affected systems to detect potential exploitation attempts early. 7. Disable or Harden Mark of the Web Handling: Where possible, configure system policies to enforce stricter handling of MotW tags or disable automatic execution of files from internet zones, though this may impact usability and should be tested carefully.