CVE-2018-8498 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-2018-8480, CVE-2018-8488, CVE-2018-8518.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability identified as CVE-2018-8498 represents a critical elevation of privilege flaw within Microsoft SharePoint Server that stems from inadequate input validation mechanisms. This weakness allows malicious actors to exploit specially crafted web requests that bypass normal security controls, potentially enabling unauthorized users to escalate their privileges and gain elevated access rights within the SharePoint environment. The vulnerability specifically targets the server-side request processing logic where SharePoint fails to properly sanitize incoming web requests, creating a pathway for attackers to manipulate the system's authorization mechanisms. This issue affects multiple versions of Microsoft SharePoint Server and demonstrates a fundamental flaw in the platform's security architecture that could be leveraged by threat actors with minimal privileges to achieve administrative access.
The technical exploitation of CVE-2018-8498 occurs through carefully constructed web requests that exploit the insufficient sanitization of user-supplied input within SharePoint's request handling pipeline. When a malicious request is processed, the server fails to adequately validate or sanitize the input parameters, allowing attacker-controlled data to be interpreted in unexpected ways. This processing error can result in the system treating the malicious request as if it originated from a privileged user, effectively bypassing authentication and authorization checks. The vulnerability is categorized under CWE-20, which specifically addresses "Improper Input Validation," highlighting the core issue of inadequate sanitization of user inputs. The flaw exists in the SharePoint Server's web request processing component where it fails to properly validate the structure and content of incoming HTTP requests before executing any privileged operations.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can enable attackers to gain full administrative control over affected SharePoint servers. Once successfully exploited, an attacker can manipulate SharePoint's core functionalities including but not limited to creating new user accounts, modifying existing permissions, accessing restricted documents, and potentially using the compromised server as a pivot point for further attacks within the network. The vulnerability's implications are particularly severe in enterprise environments where SharePoint servers often host sensitive business data and serve as central collaboration platforms. Organizations may experience unauthorized data access, potential data exfiltration, and complete compromise of their SharePoint infrastructure, all while maintaining the appearance of normal operations due to the subtle nature of the attack vector.
Mitigation strategies for CVE-2018-8498 should prioritize immediate implementation of Microsoft's security patches and updates, as the vulnerability has been addressed through official Microsoft security bulletins. Organizations must ensure all SharePoint Server installations are updated to the latest security releases, with particular attention to applying the specific fixes provided for this vulnerability. Network segmentation and monitoring should be enhanced to detect anomalous web requests that may indicate exploitation attempts, while implementing strict input validation controls at the network perimeter. Security teams should also conduct comprehensive vulnerability assessments to identify any potentially unpatched systems within their environment, and establish monitoring procedures for unusual privilege escalation activities. Additionally, implementing principle of least privilege controls and regular security audits can help minimize the potential impact of such vulnerabilities. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques, specifically noting that attackers often leverage server-side vulnerabilities to gain elevated system privileges, making proactive patch management and network monitoring essential defensive measures.