Spammers and my mail server

Posted in Commentary on February 28th, 2007 by Sacha Peter

I was going to write something, but unfortunately the bulk of my disposable time this evening was spent patching up my mail server. Apparently some spammer found a hole to send email through my server. They were sending Ebay phishing spams and my server managed to send 19,800 spams before I closed the thing down and patched up the security leak. It managed to start on February 25, while I was on vacation (nice timing on their part, maybe they read this weblog).

What a pain in the ass. Running your own mail server seems to be something suicidal these days. The only fortunate thing is that the address in the email is from some German address pretending to be from Ebay.

I apologise to all of those that were affected by my administrative ineptitude.

While looking through the server logs, however, I also noticed that somebody was brute-forcing their way into some mail accounts using very generic username and password combinations. This was to the magnitude of about 10,000 attempts per minute and I can easily see it’s time for me to pack my mail server up pretty soon – I don’t have the patience to deal with this and would prefer to outsource my mail to Bluehost. I know how to deal with problems like these – put up a firewall that will block more than 100 opened TCP connections in a minute but I don’t have such software with me.

2 Responses to “Spammers and my mail server”

  1. Justin says:

    Would it be possible to limit the number of attempts/minute?

    Doing just that will make craking into your mail accounts near impossible.

  2. Sacha says:

    The two things were independent – somebody was trying to hack through the POP3 port (to get an authenticated SMTP session which enables the server to consider you as a trusted source) but they didn’t get an account (mainly because there isn’t too much to hack on my server).

    I’m still not entirely sure how the spammer got through, there’s about 50 megabytes of log files for me to comb over when I have the time. I’ve tightened the screws on the email server a little more, there are a lot of settings dealing with authentication and stuff.

Leave a Reply