Email Aliases Exposed?

[G J Piper]

I recently moved from an older FreeBSD 6 server that I had been using since around 2003. I had been using aliases to control/track email spam on my old server. (every time I use a new company or online store, I'd make an alias email address specifically for that company, and delete it if it started getting spam)

About one month after switching to my new Plesk 12.5.30 u#24 CentOS 6.7 server, I started getting spam on some of those older aliases. Some of these aliases were only used once, a decade ago!

My question is this: How are spammers getting these email aliases on their list now? Many of these aliases are extremely obscure, and could not be getting hit by dictionary attackers. As an example, one of these aliases hasn't been used since 2004, and was only used one time for one email back and forth. Now suddenly spammers are hitting it.

Is there some way spammers are getting my list of over 70+ aliases from my new server?

I'm running Dovecot and Postfix.

 

[UFHH01]

Hi G J Piper,

Is there some way spammers are getting my list of over 70+ aliases from my new server?

No, there is NO WAY, that spammers/bots may get a list of your eMail-accounts, configured on your server. But you should inspect your mail - logs and the headers of your eMails, if you would like to investigate spam on your server.
It helps as well, to follow KB - article 114845, to investigate the source of spam on your server:

Many email messages are sent from PHP scripts on the server. How can I find the domains on which these scripts are running if I am using Postfix? ( Plesk online Knowledge-Base )​

Consider to add depending log - entries from your logs, if you need help and add as well the eMail - headers and configuration files, so that further investigations can be done.