Recent Posts

Harden a Linux host by checking services, updates, accounts, SSH, firewall rules, permissions, backups, and logs—then verify that the workload still works.

Learn how to set input contracts in C++, bound raw data, parse complete values, check arithmetic and text rules, and test malformed input.

Learn how to define failure contracts in Java, preserve exception causes, close resources, log safely, limit retries, and test error paths.

Learn to diagnose lab connection failures with built-in network commands, curl, packet captures, Nmap, firewalls, and logs—within an authorized scope.

Build branch-specific Java fixtures for browser-game signup tests, check validation and provider responses, and prevent test inputs from reaching live services.

Learn how Linux file and directory permissions work, use chmod and umask, and diagnose Permission denied errors without opening access unnecessarily.

Learn what TLS protects, how certificates verify a server, where HTTPS coverage ends, and how to diagnose connection errors without disabling verification.

Learn how to track, validate, store, display, and delete user data in a Java project, with practical checks for logs, errors, and access control.

Learn to scope an authorized incident investigation, preserve logs, build a reliable timeline, test competing explanations, and report findings with clear limits.

Learn how to generate unique passwords, protect a password manager, set up MFA, and respond when a password is exposed.