CVE-2005-1109 in Internet Junkbuster
Summary
by MITRE
The filtering of URLs in JunkBuster before 2.0.2-r3 allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via heap corruption.
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Analysis
by VulDB Data Team • 06/06/2019
The vulnerability identified as CVE-2005-1109 affects JunkBuster, a popular open-source proxy server designed to filter web content and block malicious websites. This security flaw exists in versions prior to 2.0.2-r3 and represents a critical issue that could be exploited by remote attackers to compromise the integrity and availability of the proxy service. The vulnerability stems from inadequate input validation and memory management within the URL filtering mechanism, creating a pathway for malicious actors to manipulate the application's behavior through carefully crafted input sequences.
The technical root cause of this vulnerability lies in heap corruption that occurs during URL processing within JunkBuster's filtering subsystem. When the application encounters specially crafted URLs, the memory allocation and deallocation processes become corrupted, leading to unpredictable application behavior. This heap corruption vulnerability is classified under CWE-122, which describes insufficient checking of the size of input data during memory allocation operations. The flaw manifests when the proxy server attempts to process malformed URLs that exceed expected buffer boundaries, causing memory corruption that can result in application crashes or potentially allow for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it creates a potential attack vector for more sophisticated exploitation attempts. Remote attackers can leverage this weakness to crash the JunkBuster proxy server, effectively disrupting legitimate network traffic filtering and content control services. In addition to service disruption, the heap corruption aspect introduces the possibility of arbitrary code execution, which would allow attackers to gain unauthorized control over the affected system. This represents a significant security risk for organizations relying on JunkBuster for network protection, as compromised proxy servers could be used to redirect traffic, intercept communications, or serve as launching points for further attacks within the network infrastructure.
The attack surface for this vulnerability is particularly concerning given the widespread deployment of JunkBuster in enterprise and organizational environments. According to ATT&CK framework categorization, this vulnerability maps to techniques involving denial of service and privilege escalation, with the potential for initial access through network-based exploitation. The flaw demonstrates poor input sanitization practices that align with common attack patterns documented in the cybersecurity community, where buffer overflows and memory corruption vulnerabilities represent persistent threats in network filtering applications. Organizations should consider implementing immediate mitigation strategies including patching to version 2.0.2-r3 or later, which contains the necessary memory management fixes and input validation improvements to address the heap corruption issue. Additionally, network segmentation and monitoring of proxy server traffic can help detect potential exploitation attempts and provide early warning of compromise.