CVE-2025-21294 in Windows
Summary
by MITRE • 01/14/2025
Microsoft Digest Authentication Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 01/25/2025
This vulnerability represents a critical remote code execution flaw in Microsoft's digest authentication implementation that affects multiple Windows operating systems and server products. The vulnerability stems from improper handling of authentication tokens and credential validation processes within the digest authentication mechanism, creating a pathway for attackers to execute arbitrary code on affected systems. The flaw exists in the way Windows processes authentication requests when digest authentication is enabled, particularly when handling malformed or specially crafted authentication headers that bypass normal validation procedures.
The technical exploitation of this vulnerability occurs through carefully constructed HTTP requests that manipulate the digest authentication flow to trigger memory corruption or code execution within the authentication service. Attackers can leverage this weakness by sending malicious authentication requests that cause buffer overflows or other memory management errors in the authentication subsystem. This allows remote attackers to execute code with the privileges of the authenticated service account or system administrator, depending on the target application or service using digest authentication. The vulnerability specifically impacts Windows systems where digest authentication is enabled and actively used for authentication purposes.
The operational impact of CVE-2025-21294 is severe as it provides attackers with a direct path to system compromise without requiring prior authentication credentials. This makes the vulnerability particularly dangerous in environments where digest authentication is used for web applications, file sharing services, or other network resources. Organizations running affected versions of Windows Server, IIS web servers, or applications that rely on digest authentication are at significant risk. The vulnerability can be exploited remotely over the network, potentially allowing attackers to establish persistent access, escalate privileges, and move laterally within the network infrastructure.
Mitigation strategies should focus on immediate patch application from Microsoft as the primary defense mechanism, along with disabling digest authentication where possible and implementing network segmentation controls. Organizations should also consider implementing intrusion detection systems to monitor for suspicious authentication patterns and network traffic that may indicate exploitation attempts. The vulnerability aligns with CWE-121 for buffer overflow conditions and relates to ATT&CK technique T1110 for credential access and T1075 for remote service exploitation. Additional protective measures include configuring firewalls to restrict access to authentication endpoints, implementing strong access controls for authentication services, and conducting thorough network monitoring for unusual authentication activity that could indicate exploitation attempts.