Connected Box Hint - HTB

Summary

Connected is an easy Linux machine that focuses on web application exploitation, vulnerability research, and privilege escalation through insecure system automation.

Initial Access

• Run Nmap and identify the web application running on the server.
• Find the FreePBX version from the web interface.
• Search for public vulnerabilities affecting that version.
• Metasploit may already contain a module related to the discovered vulnerability.
• Search Metasploit using keywords such as 'freepbx(version related CVE)'.
• The vulnerability exists in the Endpoint Manager component.
• The intended attack path does not require valid credentials.
• Successful exploitation should provide a shell as the asterisk user.

Root Access

• After getting a shell, start enumerating the system carefully.
• Check running processes and look for unusual services.
• The incrond service is worth investigating.
• Find out which files are being monitored by incrond.
• Look for monitored files that are writable by the asterisk user.
• Pay attention to the ha_trigger file.
• Investigate what happens when the HA service is triggered.
• Follow the execution path of the HA-related scripts.
• Check permissions on FreePBX modules and related directories.
• The intended privilege escalation involves a writable component being used by a root-owned process.
• Think about how a file-monitoring service can become dangerous when users can modify monitored files.
• The path to root is application-specific and does not require a kernel exploit.

Conclusion

Connected highlights the importance of vulnerability research, proper application hardening, and secure automation practices. The machine demonstrates how a publicly exposed application vulnerability can lead to initial access and how weak trust boundaries between privileged services and user-controlled files can result in privilege escalation. Successfully completing the machine requires a combination of enumeration, analysis, and understanding of how application components interact with system-level services.