CVE-2020-1063 in Dynamics 365 on-premises
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'.
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Analysis
by VulDB Data Team • 10/17/2020
The cross site scripting vulnerability identified as CVE-2020-1063 affects Microsoft Dynamics 365 on-premises deployments and represents a critical security flaw in the web application layer of the platform. This vulnerability stems from insufficient input validation and sanitization mechanisms within the Dynamics 365 server components that process web requests. The flaw allows malicious actors to inject malicious scripts into web pages viewed by other users, creating a persistent threat vector that can be exploited across the entire on-premises deployment environment.
The technical implementation of this vulnerability occurs when the Microsoft Dynamics 365 server fails to properly sanitize user-supplied input in web requests that are processed by the application's web interface. This improper sanitization creates an opportunity for attackers to craft malicious web requests containing script payloads that can be executed in the context of other users' browsers. The vulnerability specifically affects the server-side processing of web requests where user input is not adequately filtered or escaped before being rendered in web responses, making it a classic example of a reflected or stored cross site scripting flaw. According to CWE classification, this vulnerability maps to CWE-79 which describes improper neutralization of input during web page generation, and the ATT&CK framework categorizes this under T1059.008 for 'Command and Scripting Interpreter: PowerShell' and T1566.001 for 'Phishing: Spearphishing Attachment' as attackers may leverage this vulnerability to deliver malicious payloads through crafted web requests.
The operational impact of CVE-2020-1063 extends beyond simple script execution capabilities as it can enable attackers to perform a wide range of malicious activities within the Dynamics 365 environment. Successful exploitation allows threat actors to access sensitive data, modify user sessions, steal authentication tokens, and potentially escalate privileges within the application. The vulnerability affects all users who interact with the Dynamics 365 web interface, making it particularly dangerous in enterprise environments where the platform handles critical business data and processes. Attackers can leverage this flaw to gain unauthorized access to customer records, financial data, and other sensitive business information, potentially leading to significant financial loss and regulatory compliance violations. The on-premises nature of the vulnerability means that organizations must consider both internal and external attack vectors, as the threat landscape includes both insider threats and external adversaries attempting to exploit the vulnerable web application components.
Mitigation strategies for CVE-2020-1063 require immediate action from organizations running Microsoft Dynamics 365 on-premises installations. The primary recommended approach involves applying the official Microsoft security patches released in response to this vulnerability, which address the input sanitization deficiencies in the web request processing components. Organizations should also implement network-level protections such as web application firewalls that can detect and block malicious script payloads in web requests. Additional defensive measures include implementing strict input validation at multiple layers of the application architecture, enforcing content security policies to prevent script execution, and conducting regular security assessments of the web application components. The remediation process should include comprehensive testing to ensure that the patch does not introduce regressions in functionality while maintaining the application's ability to process legitimate user input. Security teams should also monitor for indicators of compromise related to this vulnerability and establish incident response procedures specifically addressing cross site scripting attacks against Dynamics 365 environments. Organizations may also consider implementing additional security controls such as regular security awareness training for users who interact with the Dynamics 365 platform to reduce the risk of successful exploitation through social engineering vectors.