CVE-2021-38652 in SharePoint Server
Summary
by MITRE • 09/15/2021
Microsoft SharePoint Server Spoofing Vulnerability This CVE ID is unique from CVE-2021-38651.
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Analysis
by VulDB Data Team • 09/17/2021
Microsoft SharePoint Server contains a spoofing vulnerability that allows attackers to manipulate user interface elements and potentially deceive users into performing unintended actions. This vulnerability specifically affects the way SharePoint handles certain user interface components and can be exploited to create misleading displays that appear legitimate to end users. The flaw exists in the server-side rendering mechanisms that process and display web content within the SharePoint environment.
The technical implementation of this vulnerability stems from insufficient validation of user-provided data within the SharePoint server's rendering pipeline. When SharePoint processes certain input parameters or content, it fails to properly sanitize or validate the data before incorporating it into user-facing interfaces. This allows malicious actors to inject crafted content that modifies the appearance or behavior of SharePoint pages, potentially leading to user confusion or deception. The vulnerability is particularly concerning because it operates at the presentation layer where users interact directly with the system, making it difficult to detect through traditional network monitoring approaches.
The operational impact of this vulnerability extends beyond simple visual manipulation as it can enable more sophisticated attack vectors. An attacker exploiting this weakness could potentially create fake login prompts, misleading navigation elements, or fraudulent administrative interfaces that appear authentic to users. This spoofing capability can facilitate social engineering attacks where users might unknowingly provide credentials or perform actions they would not normally undertake. The vulnerability affects multiple versions of SharePoint Server and can be leveraged by attackers with varying levels of access to the system, making it particularly dangerous in enterprise environments where SharePoint serves as a central collaboration platform.
Organizations should implement immediate mitigations including applying the relevant Microsoft security patches and updates released to address this vulnerability. Network segmentation and monitoring should be enhanced to detect unusual rendering patterns or content modifications within SharePoint environments. Security teams should also conduct thorough reviews of SharePoint configurations and implement additional validation controls for user-generated content. The vulnerability aligns with CWE-79 which addresses cross-site scripting flaws, and represents a variant of techniques described in ATT&CK tactic TA0001 (Initial Access) and TA0003 (Persistence) where attackers establish deceptive interfaces to maintain access or harvest information from unsuspecting users. Organizations should also consider implementing web application firewalls and content security policies to prevent exploitation of similar rendering vulnerabilities in their SharePoint deployments.