CVE-2016-6808 in Tomcat JK ISAPI Connector
Summary
by MITRE
Buffer overflow in Apache Tomcat Connectors (mod_jk) before 1.2.42.
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Analysis
by VulDB Data Team • 09/22/2022
The vulnerability identified as CVE-2016-6808 represents a critical buffer overflow flaw within the Apache Tomcat Connectors module known as mod_jk, which serves as a bridge between Apache HTTP Server and Tomcat application servers. This component facilitates the forwarding of requests from the web server to the application server, making it a crucial element in many enterprise web architectures. The vulnerability specifically affects versions prior to 1.2.42, indicating that organizations running older iterations of this connector were exposed to potential exploitation by malicious actors who could leverage this weakness to compromise system integrity.
The technical nature of this buffer overflow stems from inadequate input validation within the mod_jk module when processing certain HTTP headers or request parameters. When the connector receives malformed or excessively long input data, it fails to properly bounds-check the allocated memory buffers, leading to memory corruption that can be exploited to execute arbitrary code. This flaw operates at the level of the application layer and can be triggered through carefully crafted HTTP requests that manipulate header values or request parameters processed by the connector module. The vulnerability manifests as an insufficient boundary check mechanism that allows attackers to overwrite adjacent memory locations, potentially leading to stack corruption or heap-based memory corruption depending on the specific implementation details.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain unauthorized access to sensitive system resources and potentially escalate privileges within the affected environment. Organizations utilizing Apache Tomcat Connectors in production environments face significant risk if they have not upgraded to version 1.2.42 or later, since the vulnerability can be exploited remotely without requiring authentication. Attackers could leverage this weakness to deploy malicious payloads, access confidential data, or establish persistent access points within the network infrastructure. The vulnerability also poses risks to application availability, as successful exploitation could lead to service disruption or denial of service conditions.
Security practitioners should prioritize the immediate deployment of patches addressing this vulnerability, as the mod_jk module is widely deployed in enterprise environments and represents a common attack vector for sophisticated threat actors. The remediation process involves upgrading to Apache Tomcat Connectors version 1.2.42 or later, which includes proper bounds checking mechanisms and input validation routines that prevent the buffer overflow conditions. Organizations should also implement network segmentation and monitoring controls to detect potential exploitation attempts, while conducting thorough vulnerability assessments to identify any systems still running vulnerable versions. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a typical example of how legacy components can introduce persistent security risks that require continuous monitoring and patch management processes to address effectively.
The exploitation of this vulnerability demonstrates the importance of maintaining up-to-date security configurations and implementing robust security monitoring practices. Organizations should establish automated patch management systems that can identify and remediate vulnerable components across their infrastructure, particularly focusing on middleware and connector modules that form critical links in web application architectures. Additionally, implementing network-based intrusion detection systems and conducting regular security audits can help detect exploitation attempts and provide early warning capabilities for such vulnerabilities that may otherwise remain undetected for extended periods.