CVE-2016-6796 in Tomcat
Summary
by MITRE
A malicious web application running on Apache Tomcat 9.0.0.M1 to 9.0.0.M9, 8.5.0 to 8.5.4, 8.0.0.RC1 to 8.0.36, 7.0.0 to 7.0.70 and 6.0.0 to 6.0.45 was able to bypass a configured SecurityManager via manipulation of the configuration parameters for the JSP Servlet.
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Analysis
by VulDB Data Team • 09/29/2022
This vulnerability represents a critical security flaw in the Apache Tomcat web server implementation that allowed malicious applications to circumvent mandatory security restrictions through improper handling of JSP servlet configuration parameters. The issue affected multiple versions of Tomcat across its major release lines, specifically targeting versions from 6.0.0 through 9.0.0.M9, creating a widespread impact across enterprise web deployments. The vulnerability stems from a fundamental flaw in how the SecurityManager interacts with JSP servlet configuration, enabling attackers to manipulate internal parameters that should have remained protected from external influence.
The technical exploitation occurs through the manipulation of configuration parameters that control how the JSP servlet processes requests within the Tomcat container. When a malicious application attempts to bypass the SecurityManager, it exploits a design weakness where certain configuration parameters are not properly validated or restricted during runtime modification. This flaw allows unauthorized code execution within the context of the web server process, potentially enabling full system compromise. The vulnerability is classified under CWE-284 Access Control Bypass, which specifically addresses insufficient access control mechanisms that permit unauthorized users to gain access to resources or functionality.
From an operational perspective, this vulnerability creates significant risk for organizations relying on Apache Tomcat as their primary web application platform. The bypass of SecurityManager protection means that any malicious application deployed on affected Tomcat instances could potentially escalate privileges and access restricted system resources, including file system access, network communications, and execution of arbitrary code. Attackers could leverage this weakness to establish persistent backdoors, exfiltrate sensitive data, or use the compromised server as a launching point for further attacks within the network infrastructure. The impact extends beyond individual applications to potentially compromise the entire server environment.
The mitigation strategy requires immediate patching of affected Tomcat versions to the latest stable releases that contain the necessary security fixes. Organizations should also implement network segmentation and monitoring to detect potential exploitation attempts, as well as review and harden their application deployment practices to prevent unauthorized applications from being deployed on production servers. Security teams should consider implementing additional runtime protection measures and regularly audit their Tomcat configurations to ensure that SecurityManager settings remain properly enforced. This vulnerability highlights the critical importance of maintaining up-to-date web server software and proper security configuration management, as outlined in the ATT&CK framework's defense in depth principles where multiple layers of security controls are essential for protecting against such bypass attacks.