Why is this mail spam?

[Patrick Petermair]

Hi!

I've implemented mailscanner yesterday, and it seems to work fine.
However, I have a some mails, that are marked as spam and are _under_
the spamscore of 5. I have even increased "Spam Lists To Reach High
Score" to 3 instead of 2 (the mails that are marked as spam are found in
only 1 Spam List.

Here is an example from the logfile:

Mar  3 03:09:59 watt MailScanner[3426]: New Batch: Scanning 1 messages,
4177 bytes
Mar  3 03:09:59 watt MailScanner[3426]: MCP Checks completed at 4177
bytes per second
Mar  3 03:09:59 watt MailScanner[3426]: Spam Checks: Starting
Mar  3 03:10:01 watt MailScanner[3426]: RBL checks: 1AyLpd-0000tK-VF
found in spamhaus.org
Mar  3 03:10:05 watt MailScanner[3426]: Message 1AyLpd-0000tK-VF from
69.42.78.187 (bdbiflciclcdbagglbgabcgeba at dc41.com) to anecon.com is
spam, spamhaus.org, SpamAssassin (score=3.634, required 5, BAYES_90
2.10, HTML_MESSAGE 0.10, MIME_HTML_ONLY 0.32, RCVD_IN_SBL 1.11)
Mar  3 03:10:05 watt MailScanner[3426]: Spam Checks: Found 1 spam messages
Mar  3 03:10:05 watt MailScanner[3426]: Spam Actions: message
1AyLpd-0000tK-VF actions are store,deliver,striphtml
Mar  3 03:10:05 watt MailScanner[3426]: Spam Checks completed at 696
bytes per second


As you can see, 5 points are required and this mail got 3.634 and was
only in 1 RBL.
What could trigger this? I have nothing special configured (no
whitelists, no blacklists,..)

Patrick