is a popular and powerful web shell or "backdoor shell". A web shell is a malicious script uploaded to a web server that allows an attacker to execute commands and manage the server remotely through a web browser.

Use find command on Linux:

: Using tools like b374k on systems you do not own or have explicit permission to test is illegal. For legitimate learning, it is typically hosted on GitHub for study by security professionals. b374k.php · kali/master - GitLab

: It consolidates multiple administrative functions (file management, database execution, network tools) into a single, password-protected PHP file.

is a well-known, feature-rich PHP webshell often used by security researchers for penetration testing or by malicious actors to maintain unauthorized access to a web server. It provides a graphical user interface (GUI) within a web browser to manage files, execute commands, and interact with the server's operating system. Key Characteristics

Look for GET /somefile.php followed by a POST with a password parameter ( ?p= or ?pass= ). Example: