CVE-2025-32016 in Microsoft Identity Web
Summary
by MITRE • 04/09/2025
Microsoft Identity Web is a library which contains a set of reusable classes used in conjunction with ASP.NET Core for integrating with the Microsoft identity platform (formerly Azure AD v2.0 endpoint) and AAD B2C. This vulnerability affects confidential client applications, including daemons, web apps, and web APIs. Under specific circumstances, sensitive information such as client secrets or certificate details may be exposed in the service logs of these applications. Service logs are intended to be handled securely. Service logs generated at the information level or credential descriptions containing local file paths with passwords, Base64 encoded values, or Client secret. Additionally, logs of services using Base64 encoded certificates or certificate paths with password credential descriptions are also affected if the certificates are invalid or expired, regardless of the log level. Note that these credentials are not usable due to their invalid or expired status. To mitigate this vulnerability, update to Microsoft.Identity.Web 3.8.2 or Microsoft.Identity.Abstractions 9.0.0.
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Analysis
by VulDB Data Team • 04/09/2025
Microsoft Identity Web represents a critical library for ASP.NET Core applications seeking integration with Microsoft identity platform services including Azure AD v2.0 endpoint and AAD B2C. This vulnerability stems from improper handling of credential information within application logging mechanisms, creating potential exposure pathways for sensitive authentication materials. The flaw specifically targets confidential client applications including daemon processes, web applications, and web APIs that utilize the Microsoft Identity Web library for authentication purposes.
The technical implementation of this vulnerability occurs when service logs capture credential information during error conditions or normal operation. Log entries may contain client secrets, certificate details, or other authentication materials that are inadvertently written to service log files. These logs typically operate at information level or higher, where credential descriptions including local file paths containing passwords, Base64 encoded values, or direct client secret references are captured. The vulnerability extends to scenarios where certificates are invalid or expired, regardless of log level settings, as the library continues to process and potentially log credential information even when authentication materials are no longer valid.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential attack vectors for adversaries seeking to compromise authentication systems. Attackers could exploit these log files to extract client secrets, certificate information, or other sensitive credentials that might be used for lateral movement or privilege escalation within Azure environments. The risk is particularly elevated in scenarios where applications are deployed across multiple environments or where log files are not properly secured. This vulnerability aligns with CWE-200 (Information Exposure) and represents a significant concern for organizations maintaining applications that handle sensitive authentication information in cloud environments.
Security controls and mitigation strategies should focus on immediate library updates to versions 3.8.2 or 9.0.0 as recommended by Microsoft. Organizations must also implement comprehensive log management practices including log file access controls, regular log review procedures, and secure log retention policies. The ATT&CK framework categorizes this vulnerability under T1566 (Phishing) and T1078 (Valid Accounts) as attackers could leverage extracted credentials to establish persistent access. Additional defensive measures include implementing proper log sanitization techniques, ensuring credential information is not written to logs at any level, and establishing monitoring for anomalous credential usage patterns. Organizations should also consider implementing Azure Monitor and other logging solutions that can help detect and prevent unauthorized access to credential information within log files.