CVE-2011-1892 in SharePoint
Summary
by MITRE
Microsoft Office Groove 2007 SP2, SharePoint Workspace 2010 Gold and SP1, Office Forms Server 2007 SP2, Office SharePoint Server 2007 SP2, Office SharePoint Server 2010 Gold and SP1, Office Groove Data Bridge Server 2007 SP2, Office Groove Management Server 2007 SP2, Groove Server 2010 Gold and SP1, Windows SharePoint Services 3.0 SP2, SharePoint Foundation 2010, and Office Web Apps 2010 Gold and SP1 do not properly handle Web Parts containing XML classes referencing external entities, which allows remote authenticated users to read arbitrary files via a crafted XML and XSL file, aka "SharePoint Remote File Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 06/17/2025
This vulnerability represents a critical information disclosure flaw affecting multiple Microsoft SharePoint and Groove products from 2007 through 2010. The vulnerability stems from improper handling of Web Parts that contain XML classes referencing external entities, creating a path for remote authenticated attackers to access arbitrary files on the affected systems. The flaw specifically manifests when the system processes XML and XSL files that contain crafted external entity references, allowing unauthorized file access through the Web Parts infrastructure. This issue falls under CWE-20: Improper Input Validation, specifically related to XML external entity processing, and aligns with ATT&CK technique T1213.002: Data from Information Repositories, as it enables unauthorized access to stored data through web application vulnerabilities. The vulnerability affects a broad range of Microsoft collaboration and document management platforms, including SharePoint Workspace, Groove Server implementations, and various Office SharePoint Server versions, making it particularly concerning for enterprise environments that rely on these products for document sharing and collaboration.
The technical execution of this vulnerability requires an authenticated user to leverage the XML parsing behavior within the SharePoint Web Parts framework. Attackers can construct malicious XML and XSL files that reference external entities, which when processed by the vulnerable systems, can trigger file disclosure from the server filesystem. The attack vector operates through the standard SharePoint Web Parts processing pipeline where XML content is parsed and rendered, allowing the external entity references to resolve to local file paths. This creates a path traversal scenario where the XML parser resolves external entities to arbitrary file locations, potentially exposing sensitive configuration files, user data, or system files. The vulnerability's impact is significant as it allows attackers to access files that they should not be able to read, potentially including database connection strings, user credentials, or other sensitive information stored on the SharePoint servers. The flaw essentially bypasses normal access controls through XML processing mechanisms, making it particularly dangerous in environments where SharePoint servers store confidential business data.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can serve as a precursor to more serious attacks within the enterprise network. Successful exploitation can lead to data breaches, credential theft, and potential lateral movement within the network. Organizations using affected SharePoint and Groove implementations face increased risk of unauthorized data access, especially in environments where these platforms host sensitive corporate information. The vulnerability affects both the server-side processing capabilities and the client-side Web Parts rendering, meaning that users accessing compromised SharePoint sites could be exposed to additional risks. Security teams must consider this vulnerability as part of broader threat modeling exercises for SharePoint environments, as it can be combined with other techniques to escalate privileges or access additional system resources. The attack requires authentication, which reduces its immediate threat level compared to unauthenticated vulnerabilities, but still represents a significant risk within trusted network environments where insider threats or compromised credentials are possible.
Mitigation strategies should focus on implementing proper XML parsing restrictions and input validation within SharePoint environments. Organizations should apply the relevant Microsoft security updates and patches that address this specific vulnerability, as these patches typically modify how external entities are processed in XML parsers. Network segmentation and access control measures can help limit the impact of potential exploitation by restricting access to sensitive SharePoint resources. Implementing Web Application Firewalls with XML parsing rules and content filtering can provide additional protection against crafted XML and XSL files. Security monitoring should include detection of unusual file access patterns and XML processing activities within SharePoint environments. Regular security assessments of SharePoint configurations and Web Parts implementations are essential to identify and remediate similar vulnerabilities. The vulnerability highlights the importance of proper XML security practices, particularly in enterprise applications that process user-supplied XML content, and reinforces the need for regular patch management and security hardening of SharePoint environments. Organizations should also consider implementing principle of least privilege access controls to minimize the potential impact if the vulnerability is successfully exploited.