CVE-2020-17005 in Dynamics 365
Summary
by MITRE • 11/11/2020
Microsoft Dynamics 365 (on-premises) Cross-site Scripting Vulnerability This CVE ID is unique from CVE-2020-17006, CVE-2020-17018, CVE-2020-17021.
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Analysis
by VulDB Data Team • 12/04/2020
Microsoft Dynamics 365 on-premises installations contain a cross-site scripting vulnerability that represents a critical security weakness in the application's input validation mechanisms. This vulnerability falls under the CWE-79 category, which specifically addresses cross-site scripting flaws in web applications. The flaw enables malicious actors to inject malicious scripts into web pages viewed by other users, potentially compromising the entire system. The vulnerability affects the on-premises deployment model of Dynamics 365, distinguishing it from cloud-based implementations that may have different security controls. The vulnerability is particularly concerning because Dynamics 365 serves as a comprehensive business management solution that handles sensitive customer data, financial information, and operational workflows. Attackers exploiting this vulnerability could manipulate user sessions, steal authentication tokens, or gain unauthorized access to business-critical data. The attack surface is broad as the vulnerability could be triggered through various input points within the application's user interface, including forms, search functions, and data entry fields that do not properly sanitize user input.
The technical implementation of this vulnerability stems from inadequate input sanitization and output encoding within the Dynamics 365 on-premises environment. When user-supplied data is processed and rendered back to the browser without proper validation and sanitization, it creates an opportunity for attackers to inject malicious JavaScript code. This weakness is particularly evident in areas where the application dynamically generates content based on user input, such as custom forms, reports, or dashboards. The vulnerability allows attackers to execute scripts in the context of the victim's browser, potentially leading to session hijacking, data theft, or privilege escalation within the application. According to the ATT&CK framework, this vulnerability maps to T1059.007 for scripting and T1566 for social engineering techniques that could be employed to exploit this weakness. The attack requires minimal privileges to initiate, as the vulnerability exists in the application's presentation layer rather than requiring administrative access. The exploitability is enhanced by the fact that Dynamics 365 is often deployed in enterprise environments where users trust the application interface, making social engineering attacks more effective. The vulnerability's impact is amplified in environments where users have elevated privileges or where the application integrates with other enterprise systems that may be compromised through lateral movement.
The operational impact of this vulnerability extends beyond simple data theft, as it can lead to complete system compromise and business disruption. Organizations using on-premises Dynamics 365 deployments face potential exposure of sensitive customer information, financial records, and proprietary business data. The vulnerability could enable attackers to establish persistent access to the system, allowing for long-term data exfiltration and system manipulation. In enterprise environments, this vulnerability could serve as a stepping stone for attackers to move laterally within the network, particularly if the Dynamics 365 instance is integrated with other systems or databases. The attack could result in significant financial losses, regulatory penalties, and reputational damage. The vulnerability affects organizations that have not yet migrated to cloud-based solutions, as the on-premises deployment model typically requires more manual security configuration and maintenance. Security teams must consider this vulnerability as part of their overall risk assessment, particularly in environments where the application handles high-value data or serves as a central component of business operations.
Organizations should implement immediate mitigations to address this vulnerability while preparing for permanent fixes through Microsoft's security updates. The primary mitigation strategy involves implementing robust input validation and output encoding mechanisms throughout the application. This includes configuring proper sanitization of all user inputs, implementing Content Security Policy headers, and ensuring that all dynamic content is properly escaped before rendering in the browser. Organizations should also consider implementing web application firewalls to detect and block malicious payloads targeting this vulnerability. The ATT&CK framework suggests implementing defensive measures such as monitoring for suspicious script execution patterns and configuring least privilege access controls to limit the potential impact of successful exploitation. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the enterprise environment. Additionally, organizations should review their incident response procedures to ensure they can quickly detect and respond to potential exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date security patches and implementing comprehensive security monitoring across all enterprise applications, particularly those handling sensitive business data. Organizations should also consider conducting user awareness training to help identify potential social engineering attempts that could exploit this vulnerability.