CVE-2017-8551 in Project Server
Summary
by MITRE
An elevation of privilege vulnerability exists when Microsoft SharePoint software fails to properly sanitize a specially crafted requests, aka "Microsoft SharePoint XSS vulnerability".
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Analysis
by VulDB Data Team • 09/13/2024
The vulnerability identified as CVE-2017-8551 represents a critical elevation of privilege flaw within Microsoft SharePoint software that stems from inadequate request sanitization mechanisms. This weakness allows attackers to execute cross-site scripting attacks by crafting malicious requests that bypass the platform's security controls. The vulnerability specifically affects SharePoint Server 2016 and SharePoint Server 2013, making it a significant concern for organizations relying on these platforms for document management and collaboration services. The flaw resides in the way SharePoint processes user input and handles request parameters, creating an avenue for attackers to inject malicious code that can execute within the context of other users' sessions.
The technical implementation of this vulnerability demonstrates a classic cross-site scripting weakness that operates through the manipulation of request parameters within SharePoint's web interface. When SharePoint receives specially crafted requests containing malicious payloads, the software fails to properly validate or sanitize these inputs before processing them. This inadequate sanitization allows attackers to inject JavaScript code or other malicious content that can be executed by unsuspecting users who view the affected pages. The vulnerability is particularly dangerous because it can be exploited to escalate privileges from regular users to administrators, or to gain access to sensitive data and functionality within the SharePoint environment. The flaw typically manifests when users interact with SharePoint lists, libraries, or web parts that do not properly validate input parameters.
The operational impact of CVE-2017-8551 extends beyond simple data theft or disruption, as it provides attackers with the capability to establish persistent access to SharePoint environments. Once exploited, the vulnerability can enable attackers to perform actions such as creating new user accounts, modifying existing permissions, accessing confidential documents, and potentially escalating to domain-level privileges. The vulnerability's exploitation can lead to data breaches, unauthorized access to sensitive corporate information, and compromise of the entire SharePoint infrastructure. Organizations may experience significant downtime and security incidents when this vulnerability is actively exploited, as attackers can maintain access and continue to exfiltrate data over extended periods. The impact is particularly severe in environments where SharePoint serves as a central repository for intellectual property, financial records, and other sensitive business information.
Mitigation strategies for CVE-2017-8551 should prioritize immediate application of Microsoft security patches and updates to address the root cause of the vulnerability. Organizations must implement comprehensive input validation mechanisms and ensure that all user-supplied data is properly sanitized before processing within SharePoint environments. Network segmentation and access controls should be strengthened to limit the potential impact of successful exploitation attempts. Security monitoring should be enhanced to detect suspicious activities and malformed requests that may indicate exploitation attempts. Additionally, organizations should conduct regular security assessments and penetration testing to identify and remediate similar vulnerabilities within their SharePoint deployments. The mitigation approach should align with industry best practices such as those outlined in the CWE-79 category for cross-site scripting vulnerabilities and should consider ATT&CK framework techniques related to privilege escalation and credential access to ensure comprehensive protection against exploitation attempts.