Hack The Box

Exploiting CVE-2025-55182 React2Shell Vulnerability on Hack The Box Reactor Machine

A detailed walkthrough demonstrates remote code execution against a seasonal Hack The Box machine named Reactor by abusing the critical Next.js deserialization flaw CVE-2025-55182, also known as React2Shell. The attack begins with Nmap reconnaissance revealing an exposed Next.js service on port 3000, followed by Wappalyzer identification of an outdated framework version. Public exploit code is used to obtain an initial reverse shell as the node user without authentication. Credential access is achieved by extracting password hashes from the reactor.db SQLite database and cracking the engineer account with Hashcat against rockyou.txt. Privilege escalation leverages an exposed Node.js Inspector debug port on 9229, allowing WebSocket interaction via websocat to set the SUID bit on /bin/bash and obtain root access. The article highlights both the impact of the unauthenticated RCE vulnerability and common misconfigurations such as forgotten debug ports on production systems.