CVE-2017-8654 in SharePoint Server
Summary
by MITRE
Microsoft SharePoint Server 2010 Service Pack 2 allows a cross-site scripting (XSS) vulnerability when it does not properly sanitize a specially crafted web request to an affected SharePoint server, aka "Microsoft Office SharePoint XSS Vulnerability".
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Analysis
by VulDB Data Team • 01/08/2021
The vulnerability identified as CVE-2017-8654 represents a critical cross-site scripting flaw within Microsoft SharePoint Server 2010 Service Pack 2 that enables attackers to inject malicious scripts into web pages viewed by other users. This vulnerability stems from the server's inadequate sanitization of user-supplied input within web requests, creating an exploitable condition that can be leveraged for unauthorized access and data manipulation. The flaw specifically affects SharePoint Server 2010 and its Service Pack 2 implementation, making it a targeted threat for organizations utilizing this particular version of the platform. The vulnerability operates by allowing malicious actors to craft specially formatted web requests that bypass the server's input validation mechanisms, thereby enabling script execution in the context of the affected user's browser session. This particular weakness falls under the Common Weakness Enumeration category CWE-79, which specifically addresses Cross-Site Scripting vulnerabilities, and aligns with ATT&CK technique T1203, which involves exploiting web applications to execute malicious scripts. The attack surface for this vulnerability encompasses all SharePoint Server 2010 environments that process user input through web forms or URL parameters without proper sanitization.
The technical exploitation of CVE-2017-8654 occurs when an attacker crafts a malicious web request containing script code that gets processed by the SharePoint server and subsequently rendered in the browser of a victim user. The server fails to adequately validate or sanitize the input data, allowing potentially harmful JavaScript or other script code to be stored or executed within the context of the victim's session. This vulnerability is particularly dangerous because it can be exploited through various vectors including user profile information, form submissions, or URL parameters that are not properly escaped or validated. Attackers can leverage this flaw to steal session cookies, redirect users to malicious sites, or execute arbitrary commands within the victim's browser context. The vulnerability's impact is amplified by the fact that SharePoint Server 2010 was widely deployed in enterprise environments, making it a prime target for cybercriminals seeking to establish persistent access to organizational networks. The lack of proper input sanitization creates a persistent threat vector that can be exploited repeatedly, as long as the vulnerable server remains operational without appropriate patches or mitigations.
The operational impact of this vulnerability extends beyond simple script injection, potentially enabling attackers to conduct sophisticated phishing campaigns, steal sensitive information, or establish backdoor access to SharePoint environments. Organizations with compromised SharePoint servers may experience data breaches, unauthorized access to confidential documents, and potential lateral movement within their network infrastructure. The vulnerability's exploitation can lead to the compromise of user credentials, especially when combined with other attack techniques, and can serve as a launching point for more extensive security breaches. Additionally, the presence of this vulnerability can result in regulatory compliance issues, particularly in environments governed by standards such as SOX, HIPAA, or GDPR, where data protection and security controls are mandatory. The attack can also disrupt normal business operations by compromising the integrity of SharePoint sites and potentially affecting collaboration and document management workflows. Organizations may face significant financial and reputational damage if successful exploitation leads to data loss or unauthorized access to sensitive corporate information.
Mitigation strategies for CVE-2017-8654 should prioritize immediate implementation of Microsoft security patches and updates to address the root cause of the vulnerability. Organizations must ensure that SharePoint Server 2010 environments are updated to the latest available service packs and security updates from Microsoft, as these releases contain the necessary fixes to prevent the exploitation of this XSS vulnerability. Network segmentation and web application firewalls can provide additional layers of protection by monitoring and filtering malicious requests before they reach the vulnerable SharePoint servers. Input validation and output encoding should be implemented as defensive measures to sanitize all user-supplied data, particularly in areas where SharePoint processes user-generated content. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerability within the SharePoint infrastructure. Security awareness training for administrators and users can help prevent social engineering attacks that might exploit this vulnerability, while monitoring systems should be deployed to detect suspicious activities that could indicate exploitation attempts. The implementation of proper access controls and least privilege principles can limit the potential damage from successful exploitation, ensuring that even if an attacker gains access through this vulnerability, their capabilities remain constrained. Organizations should also consider migrating away from unsupported SharePoint Server 2010 versions to more current platforms that receive regular security updates and support.