CVE-2024-35255 is a vulnerability classified under CWE-362, indicating a race condition due to improper synchronization during concurrent execution of shared resources in the Microsoft Azure Identity Library for .NET, specifically version 1.0.0. This library is widely used to facilitate authentication and identity management in .NET applications interacting with Azure services. The race condition arises when multiple threads or processes access and manipulate shared data without adequate locking or synchronization mechanisms, leading to inconsistent or unexpected states. In this case, the flaw can be exploited by an attacker with limited privileges (PR:L) who has local access (AV:L) to elevate their privileges within the authentication context, potentially gaining unauthorized access to sensitive information or capabilities. The vulnerability does not require user interaction (UI:N) and affects confidentiality (C:H) but does not impact integrity or availability. The scope is unchanged (S:U), meaning the exploit affects only the vulnerable component and not other system parts. The CVSS score of 5.5 reflects a medium severity level, balancing the high confidentiality impact against the limited attack vector and required privileges. No public exploits have been reported yet, but the presence of this flaw in a core identity library suggests a significant risk if left unpatched. The vulnerability was reserved in May 2024 and published in June 2024, with no patches currently linked, indicating that remediation is pending or in progress.

For European organizations, this vulnerability poses a risk primarily to the confidentiality of sensitive authentication tokens or credentials managed via the Azure Identity Library for .NET. Organizations relying on this library in their cloud applications or internal services may experience unauthorized privilege escalation by malicious insiders or compromised local accounts. This could lead to unauthorized access to protected resources, data leakage, or lateral movement within enterprise networks. Given the medium severity and requirement for local privileges, remote exploitation is unlikely without prior access, reducing the risk from external attackers but increasing concern for insider threats or compromised endpoints. The impact is particularly relevant for sectors with stringent data protection requirements such as finance, healthcare, and government, where identity and access management are critical. Additionally, organizations heavily invested in Microsoft Azure cloud infrastructure and .NET development frameworks are more exposed. The absence of known exploits in the wild provides a window for proactive mitigation before active attacks emerge.

1. Monitor Microsoft’s official channels for patches or updates addressing CVE-2024-35255 and apply them promptly once released. 2. In the interim, review and audit all usage of the Azure Identity Library for .NET version 1.0.0 within your environment, focusing on concurrent authentication or token acquisition flows. 3. Implement additional synchronization controls or thread-safety mechanisms around shared resource access in custom code interfacing with the library. 4. Restrict local access privileges to trusted users only, minimizing the risk of exploitation by low-privilege accounts. 5. Employ endpoint detection and response (EDR) solutions to monitor for suspicious privilege escalation attempts or anomalous authentication behaviors. 6. Conduct security awareness training emphasizing the risks of local privilege abuse and the importance of secure coding practices in identity management. 7. Consider upgrading to later versions of the Azure Identity Library if available and verified to be free of this vulnerability. 8. Implement robust logging and alerting on authentication failures or unusual token requests to detect potential exploitation attempts early.