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Old 06-10-2011, 01:42 AM
jaygreg
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Default Strange SPAM

I use Thunderbird for email. My filters have been working fine and all
has been well until about 6 months ago. On an email account that is
reserved for very limited communication with a select few, I
inadvertently use it to send a message to a less computer literate
friend. She saved it and despite my request to delete it, she retains it
(though she thinks I think it's gone). I suspect someone got hold of
here address list and my special email address is one it. No matter what
I do, I cannot filter out emails that contain a strange character.
Here's an example:

AutoWarrantySales@lzed133odating.info

In desperation, I've begun looking for another email program. I stumbled
upon "Mailwasher". It claims to be compatible with Thunderbird and
appears to have the capability of blocking mail such as the above...
though I thought Thunderbird was capable as well.

Can anyone tell me anything about this character embedded type email,
how correct I may be about getting on there list, and if I'm moving in
the right direction with "Mailwasher"?

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Old 06-10-2011, 04:42 AM
VanguardLH
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Default Re: Strange SPAM

jaygreg wrote:

> I use Thunderbird for email. My filters have been working fine and all
> has been well until about 6 months ago. On an email account that is
> reserved for very limited communication with a select few, I
> inadvertently use it to send a message to a less computer literate
> friend. She saved it and despite my request to delete it, she retains it
> (though she thinks I think it's gone). I suspect someone got hold of
> here address list and my special email address is one it. No matter what
> I do, I cannot filter out emails that contain a strange character.
> Here's an example:
>
> AutoWarrantySales@lzed133odating.info
>
> In desperation, I've begun looking for another email program. I stumbled
> upon "Mailwasher". It claims to be compatible with Thunderbird and
> appears to have the capability of blocking mail such as the above...
> though I thought Thunderbird was capable as well.
>
> Can anyone tell me anything about this character embedded type email,
> how correct I may be about getting on there list, and if I'm moving in
> the right direction with "Mailwasher"?


If the account is for communication only with a select few, why not
filter out everyone except those in a specific address book or contacts
list. I don't use Tbird. In Outlook, you can define a rule that check
if the sender is in a specific contacts list:

apply this rule when the message arrives
through the <account>
delete it
except if sender is in <specified> Address Book

The Address Book is a contacts list (you can have more than one but can
only specify one in a rule). You delete all e-mails sent through the
specified account unless they were sent from someone in the specified
contacts list.

If the e-mail client lets you search within the body of e-mails, it will
be a slow process and severely lengthen how long it takes to complete a
mail poll of your account(s), especially if you cannot search through
the bodies of e-mails sent through a specific account and have to search
e-mails sent through all your accounts. Better would be to filter on
something in the headers but which you didn't provide a copy here. This
really isn't a security issue at all. It's a spam issue. For help on
how to use the headers to detect unwanted e-mails, ask in the alt.spam
newsgroup; however, you'll actually have to provide some real info on
the unwanted e-mail(s), like showing the headers for it (but munge out
the usernames for the accounts leaving the domains unmunged since those
are public anyway). While the spammer will likely mutate their fake
e-mail address everytime they spew their crap, they may include info in
the headers that is the same each time, like the language used to encode
their email. You could then define a client-side rule in your e-mail
client similarly to the one mentioned at:

http://groups.google.com/group/micro...f24a8adee28061


While you can define the client-side rule in your local e-mail client,
it would be smarter to use a server-side rule in your e-mail account.
Some e-mail providers let you set an option for Exclusive Mode (or
something similarly named) that blocks or junks all e-mails except those
from senders listed in your Address Book. So you maintain your list of
known good senders in the server-side address book (because presumably
it doesn't change very often) and any e-mails not from those folks gets
moved into the Junk or Trash folders (on the server). If you use POP
(or you use IMAP but do not subscribe to the Junk and Trash folders on
the server), you won't ever retrieve those junked or trashed e-mails;
however, they will sit in those folders for several days to let you
retrieve them from there in case someone not in your list sent you an
e-mail that you're expecting or an old contact who changed their e-mail
address.

For help with Mozilla's products, ask in their newsgroups (mozilla.*).
If your NNTP server doesn't carry them, connect it to their NNTP server
(news.mozilla.org).

By using Mailwasher, you include their use of DNSBLs (DNS blacklists) of
known spam sources. The DNSBLs are public blacklists of known spam
sources and are very effective at eliminating spam. The free version is
lureware as it is severely crippled. It will only support filtering on
just ONE account. The crippled free version supports an opt-in
(friends) list but you could the same via rules or options in your own
e-mail client. You can define filtering rules in Mailwasher but you can
already do the same in your own e-mail client. You can use regex
(regular expressions) in their filters; however, your e-mail client
might already support regex plus the vast majority of e-mail users don't
know how to use regex. Bayesian filtering should be the LAST method
employed for spam filtering as it is a guessing scheme; see
http://en.wikipedia.org/wiki/Bayesian_spam_filtering. Your e-mail
client probably already has a Bayes filter (Microsoft was one of the
last to add one in their Outlook product).

Unless you are willing to pay for a non-crippled version of Mailwasher,
don't waste your time with the free version unless filtering on just one
account is acceptable to you. If you decide to get the crippled or paid
version of Mailwasher, NEVER use its auto-bounce feature. Neither you
or your e-mail client are an e-mail server and the fake bounce can be
differentiated from one sent by a real e-mail server. Once an e-mail is
received there is no information within it to give you a guaranteed
e-mail address for the sender. You don't know with absolute assurance
what is the e-mail address of the sender. The result is you impale
innocents with your fake bounces. This backscatter is reportable as
spam. You could end up getting on the same public blacklists used in
Mailwasher because you chose to become a spam source. Below is my
canned response regarding fake bounces.

--- Why fake bounces are bad ---

The bounce feature in any e-mail client is stupid and irresponsible
primarily because ignorant users will actually believe the software
author is providing an appropriate feature and that it will somehow
avoid further spam. Spammers do not use their own e-mail address.
Instead they use a bogus one (which may be a valid e-mail address for
some user) or they use one that they've already stolen and is often
included in the recipient list of e-mail addresses. Spammers change
their e-mails every time they spew so blocking on the one they used last
time won't eliminate getting their crap when they next spew. Spammers
rely on the ignorance of e-mail users that believe using blacklists
and/or bouncing by the sender's claimed e-mail address has any effect on
reducing received spam.

- Blocking by the sender's e-mail will NOT eliminate spam in your
mailbox. The spammer's e-mail address changes at their will.

- Bouncing based on the return-path headers in an e-mail will NEVER hit
the spammer. Only boobs think the spammer will identify themself.

YOU are not connected during the mail session between the sending and
receiving mail servers so you have absolutely no means to guarantee of
knowing from the return-path headers (e.g., From or Reply-To) as to who
sent you a spam mail. The sender can put anything they want in there.
Even mail servers that first accept a message, end the mail session with
the sending mail host, and then check afterward if the e-mail address is
valid or not and then try to send a *new* message back to the sender
will get it wrong. If a valid IP address of the sender is included in a
Received header, that does NOT provide you with an e-mail address to
which you can bounce back their spam. You cannot rely on the
return-path headers to guarantee identifying the true sender. These
bounces are sent blind!

The spammer isn't going to identify themself to receive that bounce. Now
consider that only aren't you the receiving mail server but you are even
further removed from the mail session between the sending and receiving
mail hosts. There is nothing in your e-mail client that can absolutely
guarantee who is the sender of the spam you got in your Inbox, so
bouncing it anywhere means wasting bandwidth for you to send the bounce,
disk space and bandwidtch by your mail server to attempt to deliver your
bounce, disk space and CPU cycles for the receiving mail host to accept
your bogus bounce mail, and some innocent getting slapped with your
misdirected bounce (which, by the way, can be reported to blacklists as
backscatter and get you blacklisted).

Think about it for all of 10 seconds, if even that long. Would you like
to be the victim of a "mail bombing" because some spammer usurped your
e-mail address, sends out a million copies of their crap with you
identified as the sender, and then all those boobs using e-mail clients
with a bounce option end up filling your mailbox with all their
misdirected bounces?

Any e-mail client that provides a bounce option are irresponsible
software authors. Ignorant users sending misdirected bounces are
irresponsible e-mail users. Have a read at:

http://spamlinks.net/prevent-secure-...atter-fake.htm
http://spamlinks.net/prevent-secure-backscatter.htm

Warning: If you send me backscatter, like misdirected bounces which to
me are unsolicited and hence spam, I will report you to blacklists, like
at SpamCop, for your irresponsible and ignorant use of flawed anti-spam
schemes. If you punish me with your backscatter, I will punish you! I'm
not the only one with this attitude. There are plenty of spam reporters
out there and they will report you, too. It is not up to the rest of us
to placate your sensitivity for your spam problem by being your victim.
Get a responsible anti-spam solution.

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