CVE-2018-8431 in SharePoint Enterprise Server
Summary
by MITRE
An elevation of privilege vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server, aka "Microsoft SharePoint Elevation of Privilege Vulnerability." This affects Microsoft SharePoint Server, Microsoft SharePoint. This CVE ID is unique from CVE-2018-8428.
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Analysis
by VulDB Data Team • 05/08/2023
The vulnerability identified as CVE-2018-8431 represents a critical elevation of privilege flaw within Microsoft SharePoint Server environments. This security weakness arises from the server's inadequate sanitization of specially crafted web requests, allowing malicious actors to potentially escalate their privileges and gain unauthorized access to elevated system resources. The vulnerability specifically impacts Microsoft SharePoint Server and SharePoint products, creating a significant risk for organizations relying on these platforms for document management and collaboration services.
The technical flaw stems from insufficient input validation mechanisms within the SharePoint Server's web request processing pipeline. When a malicious user submits a crafted web request containing specially formatted parameters or payloads, the server fails to properly sanitize this input before processing. This inadequate sanitization allows attackers to inject malicious code or manipulate server behavior in ways that bypass normal access controls and authentication mechanisms. The vulnerability operates at the application layer, exploiting weaknesses in how SharePoint handles user-supplied data within web requests.
The operational impact of CVE-2018-8431 extends beyond simple privilege escalation, potentially enabling attackers to execute arbitrary code on affected servers with elevated privileges. This could result in complete system compromise, data exfiltration, and persistent backdoor access to organizational networks. The vulnerability is particularly dangerous because it allows attackers to operate with elevated privileges without requiring authentication, making detection and prevention significantly more challenging. Organizations may experience unauthorized access to sensitive documents, modification of critical system configurations, and potential lateral movement within their network infrastructure.
This vulnerability aligns with CWE-20, which describes improper input validation, and can be mapped to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation." The attack surface is broad given SharePoint's widespread use in enterprise environments, making it a prime target for both nation-state actors and organized cybercriminal groups. Organizations should implement immediate mitigations including applying Microsoft security patches, implementing network segmentation, and deploying web application firewalls to monitor and filter suspicious web requests. Additionally, regular security assessments and monitoring of SharePoint server logs should be conducted to detect potential exploitation attempts and ensure the effectiveness of implemented controls.