CVE-2024-49070 is a high-severity vulnerability affecting Microsoft SharePoint Enterprise Server 2016 (version 16.0.0). It is classified under CWE-502, which pertains to the deserialization of untrusted data. This vulnerability allows remote code execution (RCE) due to improper handling of serialized data inputs. Specifically, the SharePoint server improperly deserializes data from untrusted sources, enabling an attacker to craft malicious serialized objects that, when processed by the server, can execute arbitrary code. The CVSS 3.1 base score is 7.4, indicating a high severity level. The vector string (CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C) shows that the attack requires local access (AV:L), high attack complexity (AC:H), no privileges (PR:N), and no user interaction (UI:N). The vulnerability impacts confidentiality, integrity, and availability with complete control (C:H/I:H/A:H). The scope is unchanged (S:U), and there are no known exploits in the wild as of the publication date. No official patches have been linked yet, but the vulnerability is recognized and published by Microsoft and CISA. The vulnerability is critical because deserialization flaws often allow attackers to bypass security controls and execute arbitrary code, potentially leading to full system compromise. Given that SharePoint is widely used for collaboration and document management in enterprises, exploitation could lead to data breaches, disruption of business operations, and lateral movement within networks.

For European organizations, this vulnerability poses a significant risk, especially for those relying on Microsoft SharePoint Enterprise Server 2016 for internal collaboration, document management, and workflow automation. Successful exploitation could lead to unauthorized access to sensitive corporate data, intellectual property theft, and disruption of critical business processes. The high impact on confidentiality, integrity, and availability means attackers could exfiltrate data, modify or delete content, or cause denial of service. Additionally, since SharePoint often integrates with other Microsoft services and Active Directory, attackers could leverage this foothold to escalate privileges and move laterally across the network. This is particularly concerning for sectors with stringent data protection requirements under GDPR, such as finance, healthcare, and government agencies. The requirement for local access and high attack complexity somewhat limits remote exploitation but does not eliminate risk, especially in environments where insider threats or compromised internal systems exist. The absence of known exploits in the wild provides a window for proactive mitigation before active attacks emerge.

1. Immediate assessment of SharePoint Enterprise Server 2016 deployments to identify affected versions (16.0.0). 2. Restrict local access to SharePoint servers to trusted administrators and systems only, employing network segmentation and strict access controls to reduce attack surface. 3. Monitor internal network traffic and logs for unusual deserialization activity or anomalous behavior indicative of exploitation attempts. 4. Apply the principle of least privilege to all accounts interacting with SharePoint, minimizing potential damage from compromised credentials. 5. Implement application whitelisting and endpoint detection and response (EDR) solutions on SharePoint servers to detect and block unauthorized code execution. 6. Stay alert for official patches or mitigations from Microsoft and apply them promptly once available. 7. Conduct internal security awareness training to reduce insider threat risks and encourage reporting of suspicious activities. 8. Consider deploying additional runtime application self-protection (RASP) or web application firewall (WAF) solutions capable of detecting and blocking deserialization attacks. 9. Regularly back up SharePoint data and verify backup integrity to enable recovery in case of compromise.