Any account on a legitimate mail server is a valuable resource to a spammer or cybercriminal because it gives access to a server that is unlikely to be blocked from sending email. A spammer can use an account on a legitimate mail server to spam, and reach many more people…

*** This is a Security Bloggers Network syndicated blog from The Spamhaus Project authored by The Spamhaus Team. Read the original post at: https://www.spamhaus.org/resource-hub/email-security/spam-through-compromised-passwords-can-it-be-stopped