CVE-2005-0316 in Webwasher Classic
Summary
by MITRE
WebWasher Classic 2.2.1 and 3.3, when running in server mode, does not properly drop CONNECT requests to the localhost from external systems, which could allow remote attackers to bypass intended access restrictions.
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Analysis
by VulDB Data Team • 02/05/2025
The vulnerability identified as CVE-2005-0316 affects WebWasher Classic versions 2.2.1 and 3.3 when operating in server mode configuration. This represents a critical access control flaw that undermines the security posture of the proxy service by failing to properly validate incoming connection requests. The flaw specifically manifests in the handling of CONNECT requests which are fundamental to HTTP proxy operations, particularly when establishing secure connections through the proxy server. When WebWasher Classic processes these requests, it does not adequately verify the source of the CONNECT requests, allowing external systems to potentially bypass intended network access controls.
The technical implementation of this vulnerability stems from improper request validation mechanisms within the proxy server's connection handling logic. CONNECT requests are typically used in HTTP/1.1 for tunneling secure connections through proxy servers, and they should be subject to strict access controls to prevent unauthorized access to internal network resources. In this case, the WebWasher Classic implementation fails to properly authenticate or authorize the origin of CONNECT requests, creating a pathway for remote attackers to establish connections to localhost services that should remain protected from external access. This behavior directly violates fundamental principles of network segmentation and access control that are essential for maintaining security boundaries.
The operational impact of this vulnerability is significant as it allows remote attackers to potentially gain unauthorized access to internal services that are typically protected by the proxy server's architecture. Attackers could exploit this flaw to bypass access restrictions and directly connect to localhost services that are normally restricted to internal network access only. This creates opportunities for reconnaissance, data exfiltration, and potential system compromise through access to internal services that may not be properly secured. The vulnerability essentially undermines the proxy server's role as a security boundary, allowing external threat actors to circumvent network access controls that were specifically designed to protect internal resources from external threats.
The flaw aligns with CWE-284 which addresses improper access control in software systems, specifically targeting inadequate authorization mechanisms that allow unauthorized access to protected resources. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and lateral movement by enabling attackers to bypass network access controls and establish connections to internal services that should remain protected. The vulnerability also relates to technique T1071.004 which involves application layer protocol usage for proxy connections, highlighting how the improper handling of proxy protocols can create security gaps in network architectures.
Mitigation strategies for this vulnerability should focus on implementing proper request validation and access control enforcement within the WebWasher Classic proxy server. Organizations should ensure that all CONNECT requests are properly authenticated and authorized before allowing connections to localhost services. The recommended approach includes implementing strict source validation for incoming requests, configuring proper access control lists, and ensuring that proxy servers properly enforce network segmentation principles. Additionally, system administrators should consider upgrading to patched versions of WebWasher Classic if available, or implementing additional network-level controls such as firewall rules that restrict access to localhost services from external network segments. Regular security auditing of proxy server configurations should also be conducted to identify and remediate similar access control vulnerabilities that may exist in other network security tools.