Find a details on how SMTP is compromised and 50K emails were sent using linux ommand in ubuntu

Compromise of Simple Mail Transfer Protocol (SMTP) servers can occur due to various reasons, including weak passwords, vulnerabilities in software, and network misconfigurations. If an attacker gains access to an SMTP server, they can use it to send large amounts of spam email, phishing emails, and other malicious messages.

One example of compromising an SMTP server and sending out 50,000 emails using Linux command in Ubuntu could be through a brute force attack. In a brute force attack, an attacker tries multiple username and password combinations until they find the correct one. Once they have access to the SMTP server, they can use command-line tools to send large numbers of emails.

For example, the attacker could use a tool such as "sendemail" in Ubuntu to send out 50,000 emails in bulk. The following is an example command that could be used:

sendemail -f [sender email address] -t [recipient email address] -u [subject] -m [message body] -s [SMTP server address] -xu [SMTP username] -xp [SMTP password]

It's important to note that this is just one example, and there are many other methods that could be used to compromise an SMTP server and send large numbers of emails. To prevent these types of attacks, it's important to follow best practices for securing your SMTP server, such as using strong passwords, updating software regularly, and implementing network security measures.