CVE-2005-4085 in Webproxy
Summary
by MITRE
Buffer overflow in BlueCoat (a) WinProxy before 6.1a and (b) the web console access functionality in ProxyAV before 2.4.2.3 allows remote attackers to execute arbitrary code via a long Host: header.
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Analysis
by VulDB Data Team • 07/21/2024
The vulnerability identified as CVE-2005-4085 represents a critical buffer overflow flaw affecting BlueCoat proxy and security appliances, specifically targeting WinProxy versions prior to 6.1a and ProxyAV versions before 2.4.2.3. This vulnerability resides in the handling of HTTP Host headers, which are fundamental components of web requests that specify the domain name of the server being accessed. The flaw allows remote attackers to exploit the software's inadequate input validation mechanisms by sending overly long Host headers that exceed the allocated buffer space, thereby triggering a buffer overflow condition that can be leveraged for code execution.
The technical implementation of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient boundary checking allows attackers to overwrite adjacent memory locations. In the context of BlueCoat appliances, the web console access functionality serves as the primary attack vector, as it processes HTTP requests containing Host headers without proper length validation. When an attacker crafts a malicious request with an excessively long Host header, the software's memory management routines fail to handle the overflow gracefully, leading to memory corruption that can be manipulated to redirect program execution flow.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides attackers with the capability to execute arbitrary code on affected systems with the privileges of the running service. This represents a significant escalation from the initial attack surface, as it allows for complete system compromise and potential lateral movement within network environments. The vulnerability affects network security appliances that are often positioned at critical points in enterprise infrastructures, making successful exploitation particularly dangerous for organizations relying on BlueCoat solutions for web filtering and security enforcement.
From an adversarial perspective, this vulnerability maps to several ATT&CK techniques including T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) as attackers can leverage the buffer overflow to inject and execute malicious code. The attack requires minimal sophistication, as it only necessitates sending a specially crafted HTTP request with an oversized Host header, making it particularly attractive for automated exploitation campaigns. Organizations running vulnerable BlueCoat appliances face significant risk of unauthorized access, data exfiltration, and potential use as a foothold for broader network infiltration attempts.
The recommended mitigation strategies include immediate deployment of vendor patches and updates for both WinProxy and ProxyAV components, implementing network segmentation to limit exposure of vulnerable appliances, and deploying intrusion detection systems to monitor for suspicious Host header patterns. Additionally, organizations should consider implementing HTTP header length validation at network boundaries and conducting thorough security assessments of their proxy infrastructure to identify and remediate similar vulnerabilities in other components. The vulnerability demonstrates the critical importance of input validation in network security appliances and the potential consequences of inadequate memory management in enterprise security tools.