CVE-2018-8428 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. This CVE ID is unique from CVE-2018-8431.
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Analysis
by VulDB Data Team • 05/08/2023
The vulnerability described in CVE-2018-8428 represents a critical elevation of privilege flaw within Microsoft SharePoint Server environments, specifically manifesting when the platform fails to adequately sanitize web requests containing maliciously crafted data. This weakness allows authenticated attackers to potentially escalate their privileges within the SharePoint infrastructure, undermining the security boundaries that typically protect sensitive resources and administrative functions. The vulnerability stems from insufficient input validation mechanisms within the SharePoint server's request processing pipeline, creating an avenue for malicious actors to exploit the system's trust model and gain unauthorized access to elevated privileges. Such a flaw directly impacts the integrity and confidentiality of SharePoint environments where it remains unpatched, potentially enabling attackers to access restricted content, modify sensitive data, or perform administrative operations that should be limited to authorized personnel only.
The technical implementation of this vulnerability involves the exploitation of improper sanitization routines within SharePoint's web request handling mechanisms. When a specially crafted web request is processed by an affected SharePoint server, the system fails to properly validate or sanitize the incoming data before processing it within the application context. This inadequate sanitization allows malicious payload elements to bypass security controls and execute with elevated privileges, potentially enabling attackers to assume the identity of higher-privileged users within the SharePoint environment. The vulnerability specifically affects Microsoft SharePoint Server versions that lack proper input validation for web requests, creating a persistent security gap that can be exploited by attackers who have already gained initial access to the system. This flaw operates at the intersection of several security principles including input validation, privilege separation, and access control enforcement, where the failure to properly sanitize user input creates a pathway for privilege escalation attacks.
The operational impact of CVE-2018-8428 extends beyond simple privilege escalation, as it fundamentally compromises the security posture of SharePoint environments and can lead to cascading effects throughout the organization's information technology infrastructure. Attackers exploiting this vulnerability can potentially access sensitive corporate data, modify SharePoint lists and libraries, manipulate user permissions, and gain access to administrative functions that control the entire SharePoint farm. The implications are particularly severe in enterprise environments where SharePoint servers often host critical business information, document repositories, and collaborative workspaces that contain confidential data. Organizations may experience data breaches, compliance violations, and significant operational disruption when this vulnerability is exploited, as the elevated privileges gained through exploitation can enable attackers to move laterally within the network and access additional systems. The vulnerability's impact is further amplified by its potential for automated exploitation, where security tools and attack frameworks can be leveraged to systematically target unpatched SharePoint installations across organizations.
Mitigation strategies for CVE-2018-8428 should prioritize immediate patch deployment from Microsoft, as the vulnerability requires specific security updates to address the underlying sanitization flaws in SharePoint Server's request processing. Organizations must ensure comprehensive testing of patches in staging environments before deployment to avoid disrupting critical SharePoint functionality, while also implementing additional monitoring and detection measures to identify potential exploitation attempts. Network segmentation and access control measures should be strengthened to limit the potential impact of successful exploitation, including implementing least privilege principles for SharePoint server access and monitoring for unusual administrative activities. Security teams should also consider implementing web application firewalls and intrusion detection systems to monitor for suspicious web requests that may indicate exploitation attempts. The vulnerability aligns with CWE-20, which addresses "Improper Input Validation" and represents a classic example of how inadequate sanitization can create privilege escalation pathways, while also mapping to ATT&CK techniques involving privilege escalation and defense evasion through exploitation of software vulnerabilities. Organizations should conduct thorough vulnerability assessments to identify all affected SharePoint installations and prioritize remediation efforts based on risk exposure and business criticality of the impacted systems.