CVE-2023-21717 in SharePoint Foundation
Summary
by MITRE • 02/14/2023
Microsoft SharePoint Server Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 03/15/2023
Microsoft SharePoint Server contains a vulnerability that allows authenticated attackers to escalate their privileges within the system. This vulnerability stems from insufficient authorization checks in the server's permission handling mechanisms, specifically affecting how the system validates user access rights when performing administrative operations. The flaw exists in the way SharePoint Server processes certain API calls and internal permission evaluations, creating a pathway for malicious users with lower privileges to gain elevated access to system resources and administrative functions.
The technical implementation of this vulnerability involves a weakness in the server's security model where proper access control validation fails during specific administrative workflows. Attackers can exploit this by crafting malicious requests that bypass normal permission checks, effectively allowing them to perform actions that should be restricted to users with higher privileges. This type of vulnerability aligns with CWE-284 which describes improper access control issues, and represents a classic elevation of privilege scenario where an attacker can leverage existing access to gain additional capabilities within the system.
The operational impact of this vulnerability is significant as it can lead to complete system compromise when exploited by malicious actors. An attacker who successfully exploits this vulnerability could gain administrative privileges over the SharePoint Server, allowing them to modify or delete critical content, access sensitive data, manipulate user permissions, and potentially use the compromised system as a foothold for further attacks within the network. The vulnerability affects SharePoint Server versions that implement the affected permission validation logic, making it a widespread concern across organizations using these platforms.
Organizations should implement immediate mitigations including applying the latest security patches from Microsoft, reviewing and strengthening access controls, and monitoring for suspicious activities related to administrative operations. Network segmentation and monitoring solutions should be deployed to detect anomalous access patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of principle of least privilege implementation, ensuring that users only have the minimum permissions required for their legitimate operations. Security teams should conduct thorough audits of SharePoint Server configurations and user access rights to identify and remediate any potential exploitation vectors. This vulnerability demonstrates the critical importance of maintaining up-to-date security measures and proper access control implementations in enterprise collaboration platforms.