The "C99 shell" is a well-known PHP-based web shell used by attackers to remotely manage or exploit a web server. It provides a graphical interface for tasks like file management, database access, and command execution. CybelAngel ⚠️ Security Warning The C99 shell is a malware tool
int main() // C99 standard: declaring 'func' exactly where it is used void ( func)() = (void( )())shellcode; func();
The script can probe and display detailed server information, including the operating system, PHP version, server software, and memory usage. This reconnaissance data is critical for an attacker to understand the target environment and plan further exploits. shell c99 php for
Enrolling the server into a botnet to perform Distributed Denial of Service (DDoS) attacks or send spam emails. Detection and Removal Strategies
: Take the site offline to prevent further damage. Delete the File : Remove the script immediately. The "C99 shell" is a well-known PHP-based web
The script typically includes a self-delete function that removes itself from the server. This helps an attacker cover their tracks after achieving their objective or evading detection.
: The shell includes built-in tools to locate configuration files, extract database credentials, and execute SQL queries to dump tables or modify records. Environment Intelligence This reconnaissance data is critical for an attacker
#include <stdio.h> #include <stdlib.h>
: Misconfigured upload forms that allow .php files to be stored in web-accessible directories.
Capabilities to spawn a reverse connection to an attacker's machine, bypassing firewalls.
Securing a web server against C99 and similar PHP shells requires a defense-in-depth approach. 1. Harden PHP Configurations