A critical zero-click remote code execution (RCE) vulnerability, identified as CVE-2024-30103, was recently discovered in Microsoft Outlook. This flaw allows malicious actors to execute arbitrary code on a victim’s system simply by opening a specially crafted email. Review the details of this Cybersecurity Threat Advisory to limit your potential impact.

What is the threat?

CVE-2024-30103 exists due to a flaw in the allow-listing mechanism that fails to validate form server properties. Attackers can exploit this to manipulate registry paths to point to malicious executables. Once the malicious code is executed, it can steal data, install ransomware, or perform other malicious activities.

Why is it noteworthy?

Due to its zero-click nature, attackers can potentially exploit this flaw on a large scale without the need for sophisticated social engineering tactics. Successful exploitation could result in:

• Data theft of sensitive information including personal data, financial records, and intellectual property.
• System compromise leading to attackers gaining full control of the compromised system and installing ransomware, spyware, and other malicious software.
• Lateral movement in the compromised system leading to further attacks across the organization’s network.

What is the exposure or risk?

The zero-click nature of this vulnerability makes it highly dangerous, as it reduces the barriers to successful exploitation. Organizations and individuals using Outlook are at significant risk of data breaches, unauthorized access, malware propagation, and other malicious activities.

What are the recommendations?

CSB recommends the following actions to limit the impact of the zero-click Outlook vulnerability:

• Apply the patches released by Microsoft immediately to prevent exploitation.
• Implement robust email filtering, spam protection, and user education to reduce the risk of malicious emails reaching end-users.
• Employ robust endpoint security solutions with advanced threat detection capabilities to protect systems against potential attacks.
• Isolate critical systems and data to limit the potential impact of a successful attack.
• Develop a comprehensive incident response plan to effectively respond to and recover from a security breach.