CVE-2025-21348 in SharePoint Server
Summary
by MITRE • 01/14/2025
Microsoft SharePoint Server Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 01/15/2025
Microsoft SharePoint Server contains a critical remote code execution vulnerability that arises from insufficient validation of user-supplied input within the web application framework. This flaw exists in the way SharePoint processes certain HTTP requests and handles file uploads, creating an avenue for attackers to execute arbitrary code on affected systems. The vulnerability stems from improper sanitization of input parameters that are passed through the server-side processing pipeline, allowing malicious actors to inject and subsequently execute malicious payloads. Security researchers have identified this issue as a severe threat vector that could enable full system compromise when exploited successfully.
The technical implementation of this vulnerability involves the exploitation of a deserialization flaw within SharePoint's component architecture, where untrusted data is processed without adequate validation mechanisms. Attackers can craft specially formatted requests that trigger the execution path containing the vulnerable code handling logic. This particular weakness aligns with CWE-502 which catalogs deserialization vulnerabilities as a primary attack surface for remote code execution exploits. The flaw manifests when SharePoint attempts to process user-provided data through its internal parsing routines, where insufficient input filtering allows malicious content to bypass security checks. The vulnerability specifically affects multiple versions of SharePoint Server including 2016, 2019, and the latest cloud-based offerings.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can lead to complete system compromise and persistence within enterprise networks. Attackers leveraging this vulnerability can establish backdoors, escalate privileges, and move laterally across the network infrastructure without detection. The attack surface is particularly concerning given SharePoint's widespread deployment in corporate environments where it often serves as a central collaboration platform hosting sensitive business data. Organizations utilizing SharePoint Server for document management, workflow automation, and content publishing face significant risk of data breaches when this vulnerability remains unpatched. The threat landscape has been further exacerbated by the availability of automated exploitation tools that can quickly identify and exploit vulnerable installations.
Mitigation strategies should prioritize immediate deployment of Microsoft security patches and updates to address the identified vulnerability in SharePoint Server components. Organizations must implement network segmentation and access controls to limit exposure of SharePoint servers to untrusted networks while monitoring for suspicious file upload activities. Security teams should establish robust logging and monitoring procedures specifically targeting anomalous requests that may indicate exploitation attempts, particularly focusing on unusual file handling patterns and HTTP request parameters. The implementation of web application firewalls and intrusion detection systems can provide additional layers of protection by filtering malicious traffic before it reaches the vulnerable SharePoint components. Organizations should also conduct comprehensive vulnerability assessments to identify any potentially unpatched systems within their environment and establish incident response procedures to address potential exploitation attempts. Regular security awareness training for administrators and developers can help prevent configuration errors that might inadvertently expose SharePoint servers to this class of attack.