CVE-2011-1893 in SharePoint Foundation
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Microsoft Office SharePoint Server 2010, Windows SharePoint Services 2.0 and 3.0 SP2, and SharePoint Foundation 2010 allows remote attackers to inject arbitrary web script or HTML via the URI, aka "SharePoint XSS Vulnerability."
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Analysis
by VulDB Data Team • 11/20/2021
The CVE-2011-1893 vulnerability represents a critical cross-site scripting flaw affecting multiple Microsoft SharePoint products including SharePoint Server 2010, Windows SharePoint Services 2.0 and 3.0 SP2, and SharePoint Foundation 2010. This vulnerability stems from insufficient input validation and output encoding mechanisms within the SharePoint platform's handling of URI parameters. The flaw allows remote attackers to inject malicious web scripts or HTML content through carefully crafted URI inputs, potentially compromising user sessions and data integrity across SharePoint environments.
The technical implementation of this vulnerability resides in the way SharePoint processes and renders URI parameters without adequate sanitization measures. When users navigate to specifically crafted URLs containing malicious payloads, the SharePoint application fails to properly encode or filter the input data before displaying it in web pages. This creates an environment where attacker-controlled content can be executed within the context of authenticated users' browsers, leveraging the trust relationship between the user and the SharePoint application. The vulnerability specifically impacts the URI handling components of SharePoint's web application layer, where user-provided parameters are directly incorporated into dynamic web content without proper security controls.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable sophisticated attack vectors including session hijacking, credential theft, and data exfiltration. Attackers can leverage this flaw to steal session cookies, redirect users to malicious sites, or manipulate SharePoint interface elements to perform unauthorized actions. The vulnerability affects both anonymous and authenticated users, making it particularly dangerous in enterprise environments where SharePoint serves as a central collaboration platform. Security researchers have classified this as a medium to high severity vulnerability due to its potential for privilege escalation and the ease with which attackers can craft exploitable payloads. Organizations utilizing SharePoint platforms are particularly at risk as this vulnerability can be exploited through simple web requests without requiring authentication or specialized tools.
Mitigation strategies for CVE-2011-1893 should focus on immediate patch deployment and input validation enhancements. Microsoft released security updates specifically addressing this vulnerability in their regular security bulletins, and organizations should prioritize applying these patches to all affected SharePoint installations. Network-level protections including web application firewalls and input filtering rules can provide additional defense-in-depth measures. Implementing strict output encoding for all URI parameters and establishing comprehensive input validation controls will significantly reduce the attack surface. Organizations should also consider implementing security awareness training for administrators and users to recognize potential exploitation attempts. From a compliance perspective, this vulnerability aligns with CWE-79 which addresses cross-site scripting flaws, and maps to ATT&CK technique T1059.007 for script injection. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of this vulnerability across SharePoint environments.