tmpmail. anonymous receiving SMTP server / honeypod

Idea

tmpmail is a receiving SMTP server with focus on simplicity and security for research purposes. Basically every received email is stored in a mysql database.

Features:

• accepts RFC 5321 compliant SMTP clients.
• all emails are stored in a mysql database for further processing or research.
• no MIME parser, no header parser - reduces the attack surface. If such parsers are needed in the future, they must be implemented somewhere else, e.g. in Webbrowser client-side logic.
• no authentication
• The server is implemented in fewer than 300 lines of Erlang code.
• per line timeout against denial-of-service attacks or broken TCP connections
• fancy CGI-based reader

Installation / Running

• Install erlang

• Clone the git repository:

    # cd /opt
    # git clone https://github.com/bef/tmpmail.git
  

• Clone mysql library

    # cd /opt/tmpmail
    # git clone https://github.com/Eonblast/Emysql
  

• Copy/edit etc/foo.cfg and etc/cgi.cfg.

• Create a dedicated mysql database:

    mysql> CREATE DATABASE tmpmail;
    mysql> CREATE USER 'tmpmail'@'localhost' IDENTIFIED BY 'some_pass';
    mysql> GRANT ALL PRIVILEGES ON tmpmail.* TO 'tmpmail'@'localhost';
    mysql> FLUSH PRIVILEGES;
  

• Run - it's probably best to use a screen or tmux terminal multiplexer. There is no daemon mode.

    user$ ./foo.erl
  

• tmpmail should listen on an unprivileged port >1024. Connections to port 25 can be redirected, e.g.

    # iptables -t nat -A PREROUTING -d 10.0.0.1 -p tcp --dport 25 -j DNAT --to-destination 127.0.0.1:8025