CVE-2021-41353 in Dynamics 365
Summary
by MITRE • 10/13/2021
Microsoft Dynamics 365 (on-premises) Spoofing Vulnerability
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Analysis
by VulDB Data Team • 10/15/2021
This vulnerability resides within Microsoft Dynamics 365 on-premises deployments and represents a significant spoofing flaw that could enable attackers to manipulate authentication processes and potentially gain unauthorized access to critical business systems. The issue stems from insufficient validation mechanisms within the authentication flow, allowing malicious actors to craft deceptive authentication requests that appear legitimate to the system. Such vulnerabilities are particularly dangerous in enterprise environments where Dynamics 365 serves as a central platform for customer relationship management, enterprise resource planning, and business process automation. The flaw specifically affects the way the system handles authentication tokens and session management, creating opportunities for attackers to exploit trust relationships between components.
The technical implementation of this vulnerability involves weaknesses in the authentication protocol handling where the system fails to properly validate the authenticity of incoming authentication requests. Attackers can leverage this by crafting malicious requests that bypass standard authentication checks, potentially leading to unauthorized access to sensitive business data, modification of customer records, or disruption of critical business processes. This type of vulnerability aligns with CWE-345 Insufficient Verification of Data Authenticity, which specifically addresses scenarios where systems fail to adequately verify the authenticity of data inputs. The attack vector typically involves intercepting or manipulating authentication tokens and leveraging the system's trust model to impersonate legitimate users or processes.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential data breaches, business disruption, and regulatory compliance violations. Organizations using on-premises Dynamics 365 deployments face significant risk as attackers could exploit this flaw to access sensitive customer information, financial records, and operational data that the system manages. The vulnerability's presence in on-premises installations creates additional complexity since organizations must manage their own security patches and updates, potentially leading to delayed remediation. This type of attack maps to ATT&CK technique T1566.002 Phishing: Spearphishing Attachment, where attackers could use the spoofing capability to establish persistent access through compromised legitimate user credentials.
Mitigation strategies for this vulnerability require immediate patching from Microsoft as part of their regular security update cycle, while organizations should also implement additional security controls such as enhanced monitoring of authentication events, implementation of multi-factor authentication, and network segmentation to limit the potential impact of successful exploitation. Security teams should also conduct thorough vulnerability assessments to identify any other systems that might be vulnerable to similar spoofing attacks. The remediation process should include verification that authentication tokens are properly validated and that the system maintains proper session integrity throughout the authentication process. Organizations should also consider implementing additional logging and alerting mechanisms to detect anomalous authentication patterns that might indicate exploitation attempts.