Into.the.Void.

Lately the amount of spam with russian encoding/charset that I was getting had increased significantly. Spamassassin’s configuration options “ok_locales” and “ok_languages” were not enough because I didn’t want to whitelist some language, but I just wanted to blacklist some.

So the solution for my problems was the addition of the following lines in the configuration of spamassassin:

header LOCAL_CHARSET_RUSSIAN Subject:raw =~/\=\?koi8-r\?/i
score LOCAL_CHARSET_RUSSIAN 7
describe LOCAL_CHARSET_RUSSIAN Contains russian charset that is not acceptable

If you want to add even more charsets:

header LOCAL_CHARSET_BLOCKED Subject:raw =~/\=\?(koi8-r|windows-1251)\?/i
score LOCAL_CHARSET_BLOCKED 5
describe LOCAL_CHARSET_BLOCKED Contains charsets that are not acceptable

Be VERY careful with these rules if you place them in the global config (/etc/spamassassin/local.cf) because if any of your users are getting emails in russian those emails will be probably marked as spam!!

Filed by kargig at 13:27 under Internet
Tags: charset, email, russian, spam, spamassassin
2 Comments | 13,653 views

GrRBL
In the beginning of the year I announced my RBL for Greek spam emails. The blacklist is growing larger by the day, thanks to some really kind people forwarding me their Greek spam emails, and has reached more than 120 IP addresses of verified Greek spammers.This alone though is not enough.

Why
Some spammers use their aDSL lines which have dynamic IPs to send their massive email “newsletters”. These people are split into 2 sub-categories. The ones that use their own PC as an SMTP server and the ones who use their ISP’s mail server as SMTP. I’ve tried to complain to some of their ISPs…some replied back saying that they were willing to look into the issue (but did nothing at all in the end) and others did not even reply to me. For both sub-categories, GrRBL is ineffective since I can’t add dynamic IPs in the blacklist nor can I add the IPs of the email servers of those major Greek ISPs.

Another category of spammers is the one that uses their gmail/yahoo accounts to send their emails. GrRBL is ineffective for this category as well since I can’t add gmail/yahoo to the blacklist…

What
So there was no alternative but to gather all those email addresses of these 2 categories above and add them to a new blacklist, one that will contain email addresses. I use this blacklist with my spamassassin configuration to eliminate Greek spam that GrRBL can’t. Each time I receive (or someone forwards me) a new Greek spam, I add the “From:” email address to this new blacklist. This new blacklist grows far more aggressively than GrRBL since it’s a lot easier to gather the data and already has more than 140 addresses.

Distribution
There are two available formats of the blacklist, one ready for use by spamassassin and another one with clear formatting ready to be used even by SMTPs to drop these spam emails without even touching your inbox.
The blacklist is currently only distributed to a group of well trusted people and it is available only through rsync with a username/password.

I don’t want to make the list completely public yet, but if you are interested you can request it at the contact email of GrRBL and I will reply to you about accessing it.

Sidenote
If you need a good tool to check a host again some RBLs, adnsrblcheck by Yiorgos Adamopoulos is the way to go (and it includes GrRBL!)

Filed by kargig at 23:15 under Linux,Networking
Tags: blacklist, email, Greek, greek spam, grrbl, Internet, Linux, Networking, spam, spamassassin
3 Comments | 18,388 views

It’s been some months now that I’ve started collecting some IP addresses of well known Greek spammers and I’ve put them on an DNSBL. I’ve named this list GrRBL. The software I use to run the list is rbldnsd.

The list is strictly moderated by me and only me and I try to be very selective on hosts I add to the list. The list contains hosts not only in .gr zone but also “foreign” hosts used to send spam messages either in Greek language or of Greek interest.

There’s a minimalistic guide on using it with spamassassin, exim, sendmail and postfix on GrRBL’s website. There are currently no statistics and no public listing of IPs in the blacklist. If there’s enough demand for statistics I might create some.

There’s also NO automatic deletion support, once an IP is in the list there’s no automatic way out. Since I am the only one adding IPs to the list, I am also the only one removing them, manually of course.

Even though I use GrRBL in all of the mail servers I own/manage, still I consider the service as beta. I don’t think it’s ever going to eat your emails, but you are still the only one responsible if this happens.

To submit new spam messages for inclusion please send me an email with FULL headers of the spam message to grrbl [at] void [dot] gr and I will try to take a look at it as soon as possible.

If you use it, or plan to, please leave a comment or even better, submit some spam messages so the list gets bigger and better.

P.S. In case you wonder, yes the list contains the IPs of the notorious sofokleous10 spammer.

Filed by kargig at 15:48 under Internet,Linux
Tags: antispam, blacklist, dnsbl, email, exim, grrbl, postfix, rbl, sendmail, spam, spamassassin
11 Comments | 11,464 views