CVE-2023-21573 in Dynamics 365
Summary
by MITRE • 02/14/2023
Microsoft Dynamics 365 (on-premises) Cross-site Scripting Vulnerability
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Analysis
by VulDB Data Team • 03/15/2023
Microsoft Dynamics 365 on-premises installations contain a cross-site scripting vulnerability that arises from inadequate input validation and output encoding within the application's web interface. This vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in web applications. The flaw exists in the way the system processes user-supplied data when rendering web pages, particularly in areas where dynamic content is generated based on user inputs. Attackers can exploit this weakness by injecting malicious script code through various input vectors including form fields, URL parameters, or API endpoints that do not properly sanitize or encode user-provided data before displaying it to other users. The vulnerability is particularly concerning in enterprise environments where Dynamics 365 serves as a central business application handling sensitive customer and operational data. When successfully exploited, the XSS payload can execute in the context of other users' browsers, potentially allowing attackers to steal session cookies, perform unauthorized actions on behalf of victims, or redirect users to malicious websites. This type of vulnerability aligns with ATT&CK technique T1531 which focuses on credential access through web application attacks and can facilitate broader compromise of the enterprise environment. The impact extends beyond simple data theft as attackers can leverage this vulnerability to establish persistent access or escalate privileges within the Dynamics 365 environment. Organizations using on-premises deployments are particularly at risk since they maintain their own infrastructure and may not receive automatic security updates that would be available in cloud deployments. The vulnerability's exploitation typically requires minimal technical skill and can be automated using readily available tools, making it attractive to threat actors seeking to gain unauthorized access to enterprise systems. The attack surface includes various components of the Dynamics 365 platform where user input is processed and displayed, potentially affecting multiple modules and functionalities within the application. Security professionals should note that this vulnerability represents a critical risk to organizations relying on on-premises Dynamics 365 installations, as it can serve as a foothold for more sophisticated attacks targeting the broader enterprise infrastructure. The lack of proper input sanitization and output encoding creates a persistent threat that can be exploited repeatedly until patched, emphasizing the importance of immediate remediation efforts. Organizations should implement comprehensive monitoring and logging of user activities within the Dynamics 365 environment to detect potential exploitation attempts and establish proper access controls to limit the damage that could result from successful attacks. The vulnerability demonstrates the critical need for robust web application security practices including proper input validation, output encoding, and regular security assessments to prevent similar issues in enterprise applications.