How do you use 'smtp-user-enum' to enumerate SMTP users?

To use the smtp-user-enum tool to enumerate SMTP users, you can follow these general steps:

1. Install smtp-user-enum: If you haven't already installed it, you can typically find it in your package manager or download it from its repository.

2. Run the tool: Use the following command format to enumerate users:

   smtp-user-enum -M VRFY -U userlist.txt -t target.smtp.server

   • -M VRFY: This option specifies the method to use for enumeration (VRFY, EXPN, etc.).
   • -U userlist.txt: This option specifies the file containing the list of usernames you want to check.
   • -t target.smtp.server: This is the target SMTP server you want to enumerate users on.

3. Analyze the output: The tool will provide output indicating which users exist on the SMTP server based on the responses received.

Make sure to have permission to perform this action on the target server, as unauthorized enumeration can be considered malicious activity.