CVE-2020-1049 in Dynamics 365
Summary
by MITRE
A cross site scripting vulnerability exists when Microsoft Dynamics 365 (on-premises) does not properly sanitize a specially crafted web request to an affected Dynamics server, aka 'Microsoft Dynamics 365 (On-Premise) Cross Site Scripting Vulnerability'. This CVE ID is unique from CVE-2020-1050.
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Analysis
by VulDB Data Team • 05/08/2025
The cross site scripting vulnerability identified as CVE-2020-1049 represents a critical security flaw within Microsoft Dynamics 365 on-premises deployments that exposes organizations to persistent threat vectors. This vulnerability stems from the inadequate sanitization of web requests processed by the affected Dynamics server, creating an exploitable condition where malicious actors can inject malicious scripts into web applications. The flaw specifically manifests when the system fails to properly validate and sanitize user input within web requests, allowing attackers to craft specially designed payloads that bypass security controls. This type of vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a fundamental web application security weakness that enables attackers to execute scripts in the context of other users.
The technical implementation of this vulnerability occurs at the input validation layer within the Dynamics 365 server architecture, where web requests containing malicious payloads are not adequately filtered or escaped before being processed and rendered to end users. When legitimate users interact with the vulnerable system, the malicious scripts embedded in the crafted requests execute within their browser context, potentially leading to session hijacking, data theft, or unauthorized access to sensitive business information. The attack surface is particularly concerning for on-premises deployments where organizations may have limited visibility into patch management processes and may not receive automatic security updates. The vulnerability's impact extends beyond simple script execution as it can facilitate more sophisticated attacks such as credential theft or privilege escalation within the Dynamics 365 environment.
The operational consequences of CVE-2020-1049 are severe for organizations utilizing Microsoft Dynamics 365 on-premises solutions, as successful exploitation could result in complete compromise of the customer relationship management system. Attackers leveraging this vulnerability can potentially access sensitive customer data, manipulate business processes, and gain unauthorized administrative privileges within the Dynamics 365 environment. The threat landscape for this vulnerability aligns with ATT&CK technique T1531 which focuses on credential access through web application exploitation, making it particularly dangerous for enterprises that rely heavily on Dynamics 365 for business operations. Organizations may experience significant financial and reputational damage if attackers successfully exploit this vulnerability to access confidential customer information or disrupt critical business processes. The on-premises nature of the deployment compounds the risk as organizations must maintain their own security infrastructure and patch management processes, which may not be as robust as Microsoft's cloud-based solutions.
Mitigation strategies for CVE-2020-1049 should prioritize immediate implementation of Microsoft security patches and updates, as well as the deployment of web application firewalls to filter malicious requests before they reach the Dynamics 365 servers. Organizations should implement comprehensive input validation controls and output encoding mechanisms to prevent script injection attacks, while also establishing regular security assessments to identify potential vulnerabilities in their on-premises deployments. Network segmentation and access controls can help limit the potential impact of successful exploitation, while security monitoring should be enhanced to detect suspicious activities related to web request patterns. The vulnerability highlights the importance of maintaining up-to-date security practices for on-premises solutions, as organizations may be more vulnerable to attacks due to delayed patch deployment and limited security monitoring capabilities compared to cloud-based environments. Regular security awareness training for administrators and developers is also crucial to ensure proper implementation of secure coding practices and recognition of potential attack vectors.