CVE-2015-2476 in Windows
Summary
by MITRE
The WebDAV client in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 supports SSL 2.0, which makes it easier for remote attackers to defeat cryptographic protection mechanisms by sniffing the network and conducting a decryption attack, aka "WebDAV Client Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 11/28/2024
The CVE-2015-2476 vulnerability represents a critical cryptographic weakness in Microsoft Windows WebDAV client implementations across multiple operating system versions. This vulnerability specifically targets the WebDAV client component that handles secure communication protocols, creating a pathway for attackers to compromise the confidentiality of network traffic. The flaw exists in Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 systems. The vulnerability stems from the client's support of SSL 2.0 protocol, which has been deprecated due to inherent security weaknesses and known cryptographic vulnerabilities. According to CWE-327, this represents a weakness in cryptographic implementation where the use of insecure protocols undermines the overall security posture of the system. The vulnerability enables man-in-the-middle attacks and passive network sniffing scenarios where attackers can intercept and decrypt sensitive information transmitted through WebDAV connections.
The technical exploitation of this vulnerability occurs when a WebDAV client attempts to establish a secure connection to a remote server that supports SSL 2.0. This creates an opportunity for attackers to downgrade the connection from more secure protocols like TLS 1.0 or higher to the insecure SSL 2.0 protocol. The SSL 2.0 protocol suffers from fundamental cryptographic flaws including weak key exchange mechanisms and vulnerability to known plaintext attacks. When the WebDAV client accepts SSL 2.0 connections, it essentially provides attackers with a backdoor to capture and decrypt network traffic without requiring sophisticated cryptographic attacks. The vulnerability operates at the application layer and affects the transport layer security mechanisms, making it particularly dangerous for enterprise environments where sensitive data is frequently transmitted through WebDAV connections. This weakness directly relates to the ATT&CK technique T1041, where adversaries use network sniffing and decryption attacks to gain access to sensitive information.
The operational impact of CVE-2015-2476 extends beyond simple information disclosure, as it represents a fundamental breakdown in the security architecture of affected Windows systems. Organizations running these vulnerable systems face increased risk of data breaches, intellectual property theft, and unauthorized access to sensitive corporate information. The vulnerability particularly affects environments where WebDAV is used for file sharing, document management, and collaborative work scenarios. Attackers can leverage this weakness to intercept authentication credentials, business documents, financial records, and other confidential data transmitted through WebDAV connections. The risk is compounded by the fact that the vulnerability affects multiple versions of Windows, making it challenging for organizations to remediate across their entire infrastructure. According to security best practices and industry standards, this vulnerability should be addressed immediately through patch management processes, as the cryptographic weaknesses in SSL 2.0 have been well-documented since the early 2000s. The vulnerability also impacts the overall security posture of networks by providing attackers with a method to bypass encryption controls and establish persistent access to sensitive resources.
Mitigation strategies for CVE-2015-2476 should focus on disabling SSL 2.0 support in WebDAV client configurations and implementing comprehensive patch management programs. Microsoft released security updates that addressed this vulnerability, and organizations should prioritize deployment of these patches across all affected systems. Network administrators should also implement monitoring solutions to detect attempts to establish SSL 2.0 connections and configure firewalls to block SSL 2.0 traffic. The recommended approach involves disabling SSL 2.0 support at the system level through registry modifications or group policy settings, as well as ensuring that all WebDAV clients are configured to use only secure protocols such as TLS 1.0 or higher. Additionally, organizations should conduct vulnerability assessments to identify any remaining instances of SSL 2.0 support and implement network segmentation to limit the attack surface. The remediation process should also include regular security audits to ensure that no legacy applications or configurations are inadvertently enabling SSL 2.0 support, as this vulnerability demonstrates the critical importance of maintaining up-to-date cryptographic standards and the dangers of supporting deprecated security protocols in enterprise environments.