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Apache Tomcat exploitation is a critical topic in web application security. Apache Tomcat is one of the most widely deployed Java application servers, powering enterprise web applications across industries. When Tomcat instances are misconfigured - particularly with default or weak credentials on the Manager application - attackers can deploy malicious web applications and gain remote code execution on the server.

Understanding Tomcat Manager Exploitation

The Tomcat Manager is a web-based administration interface that allows authorized users to deploy, undeploy, and manage web applications (WAR files). In many real-world scenarios, administrators leave the Manager application accessible with default credentials like tomcat:tomcat or other weak password combinations. Once an attacker gains access to the Manager, they can upload a malicious WAR file containing a web shell or reverse shell, effectively gaining command execution on the target server with the privileges of the Tomcat process.

WAR File Deployment Attacks

WAR (Web Application Resource) files are the standard packaging format for Java web applications. Attackers can craft malicious WAR files containing JSP web shells that provide interactive command execution through a web browser. Tools like msfvenom can generate reverse shell payloads packaged as WAR files, while custom JSP shells offer more flexibility. The deployment process is straightforward - upload through the Manager interface, and the malicious application becomes immediately accessible on the server.

From Web Shell to Root Access

Gaining a web shell through Tomcat is typically just the beginning of a penetration test. The Tomcat process usually runs as a limited user, so attackers must enumerate the system for privilege escalation vectors. Common escalation paths include misconfigured sudo permissions, SUID binaries, writable cron jobs, and kernel exploits. Understanding this full attack chain - from initial reconnaissance and credential discovery through web shell deployment to Linux privilege escalation - is essential for security professionals conducting comprehensive penetration tests.