CVE-2017-0195 in SharePoint Server
Summary
by MITRE
Microsoft Excel Services on Microsoft SharePoint Server 2010 SP1 and SP2, Microsoft Excel Web Apps 2010 SP2, Microsoft Office Web Apps 2010 SP2, Microsoft Office Web Apps Server 2013 SP1 and Office Online Server allows remote attackers to perform cross-site scripting and run script with local user privileges via a crafted request, aka "Microsoft Office XSS Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 11/28/2022
The vulnerability identified as CVE-2017-0195 represents a critical cross-site scripting flaw that affects Microsoft Excel Services and related web applications within the SharePoint and Office Web Apps ecosystem. This vulnerability specifically targets Microsoft SharePoint Server 2010 versions with SP1 and SP2, Excel Web Apps 2010 with SP2, Office Web Apps 2010 with SP2, Office Web Apps Server 2013 with SP1, and Office Online Server implementations. The flaw enables remote attackers to execute malicious scripts within the context of a user's browser session, potentially escalating privileges to the level of the local user account. This represents a significant security risk as it allows adversaries to manipulate web applications and potentially gain unauthorized access to sensitive data or system resources.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the Excel Services component of Microsoft's web applications. When processing user-supplied data through crafted requests, the affected systems fail to properly sanitize or escape special characters that could be interpreted as executable script code. This weakness creates an opening for attackers to inject malicious JavaScript or other script payloads that execute within the victim's browser environment. The vulnerability specifically manifests when the application processes data from untrusted sources without adequate sanitization, allowing malicious input to be rendered as executable code rather than being treated as plain text or data. According to CWE classification, this vulnerability maps to CWE-79 which describes improper neutralization of input during web page generation, specifically covering cross-site scripting scenarios.
The operational impact of CVE-2017-0195 extends beyond simple script execution to include potential privilege escalation and data compromise within the targeted environments. Attackers can leverage this vulnerability to execute scripts with the privileges of the local user account, potentially enabling them to access sensitive documents, manipulate data within Excel services, or even escalate to higher privilege levels within the system. The attack surface is particularly concerning in enterprise environments where SharePoint servers host sensitive business data and where users may have elevated permissions. The vulnerability's remote exploitability means that attackers do not require physical access or network proximity to the target systems, making it particularly dangerous for organizations with remote workers or cloud-based deployments.
Organizations affected by this vulnerability should implement immediate mitigation strategies to protect their systems from exploitation attempts. Microsoft has released security updates and patches for this vulnerability that should be deployed as a priority across all affected systems. The recommended approach includes applying the latest security updates from Microsoft, implementing proper input validation controls, and configuring web application firewalls to detect and block suspicious requests. Additionally, organizations should consider implementing content security policies to prevent script execution in web applications and conduct regular security assessments to identify potential exploitation vectors. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting web application exploitation methods that leverage client-side scripting vulnerabilities. Security teams should also implement network monitoring to detect suspicious traffic patterns and establish incident response procedures to address potential exploitation attempts.