CVE-2022-44691 is a high-severity remote code execution (RCE) vulnerability affecting Microsoft Office LTSC 2021, specifically within the OneNote component. The vulnerability allows an attacker to execute arbitrary code on a victim's system by convincing the user to open a specially crafted OneNote file or content. The CVSS 3.1 base score is 7.8, indicating a high impact. The attack vector is local (AV:L), meaning the attacker must have local access or deliver the malicious file through a local means, such as email or removable media. The attack complexity is low (AC:L), requiring no special conditions beyond user interaction (UI:R). No privileges are required (PR:N), so an unprivileged user or external attacker can exploit it if they can get the victim to open the malicious content. The vulnerability impacts confidentiality, integrity, and availability (all rated high), allowing full system compromise. The scope is unchanged (S:U), meaning the exploit affects only the vulnerable component without impacting other system components beyond the compromised application. The exploit requires user interaction, typically opening a malicious OneNote file or content. No known exploits in the wild have been reported as of the published date (December 13, 2022). The vulnerability was reserved on November 3, 2022, and published shortly after. No patch links are provided in the data, but Microsoft typically issues security updates for Office LTSC products. This vulnerability is critical for environments where Microsoft Office LTSC 2021 is used, especially in scenarios where users may open untrusted OneNote files or content, such as email attachments or shared network drives.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Microsoft Office products, including LTSC 2021, across enterprises, government agencies, and critical infrastructure sectors. Successful exploitation could lead to full system compromise, data theft, disruption of business operations, and potential lateral movement within networks. Confidentiality breaches could expose sensitive personal data protected under GDPR, leading to regulatory penalties and reputational damage. Integrity and availability impacts could disrupt business continuity, especially in sectors relying heavily on document collaboration and note-taking, such as finance, healthcare, and public administration. The requirement for user interaction means phishing or social engineering campaigns could be leveraged to deliver the exploit, increasing the risk in organizations with less mature security awareness programs. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits over time. Organizations using Microsoft Office LTSC 2021 should prioritize addressing this vulnerability to prevent potential targeted attacks.

1. Apply official Microsoft security updates promptly once available for Office LTSC 2021 to remediate the vulnerability. 2. Implement strict email filtering and attachment scanning to detect and block malicious OneNote files or suspicious content. 3. Educate users on the risks of opening unsolicited or unexpected OneNote files, emphasizing caution with email attachments and links. 4. Employ application control or whitelisting solutions to restrict execution of unauthorized or suspicious files. 5. Use endpoint detection and response (EDR) tools to monitor for anomalous behavior indicative of exploitation attempts, such as unexpected OneNote process activity or code execution patterns. 6. Limit the use of OneNote or restrict its capabilities in high-risk environments if possible, or consider alternative secure note-taking solutions. 7. Enforce network segmentation to contain potential compromise and limit lateral movement if exploitation occurs. 8. Regularly review and update incident response plans to include scenarios involving Office application exploitation. These measures go beyond generic patching advice by focusing on user awareness, detection, and containment strategies tailored to the nature of this vulnerability.