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Is E-Mail Obscuration Worth It? 204

Posted by Cliff from the minor-annoyances dept.
ThenAgain asks: "Many sites obscure e-mail addresses by adding noise (like 'STOPSPAM') or by translating the punctuation into words (Ex: 'me at domain dot com'). This makes users feel good but does it actually help? Ten lines of perl could defeat any of the present schemes with ease and the spammers have shown plenty of adaptability. So if we're not helping hold back the flood of spam, why are we decreasing the utility of the web by eliminating mailto tags and forcing users to hand-correct the addresses in their mail clients?"
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Is E-Mail Obscuration Worth It? More

Is E-Mail Obscuration Worth It?

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  • first post? (Score:5, Insightful)

    by Sdevine ( 159969 ) on Monday January 19, 2004 @11:27PM (#8028263)
    I'd say the obfuscation makes us feel better and the spammers don't care anyway. they have millions of addresses and more everyday from folks who don't take a second to obfuscate..

  • Because... (Score:5, Interesting)

    by Hanji ( 626246 ) on Monday January 19, 2004 @11:32PM (#8028287)
    Ten lines of perl could defeat any of the present schemes with ease...

    Yes, but, for now at least, there are still plenty of addresses from people who don't spam-guard, enough that writing those 10 lines of perl isn't even really worth it.

    Also, if you have your address spam-guarded, it's effectively a message to the spammers that, "I'm not one of the .01% of people who responds to this crap, and anything you send me will just hit my spam-filter anyways, so don't even try."

    And they don't, because it's just not worth it for both those reasons.

    • Re:Because... (Score:5, Insightful)

      by Babbster ( 107076 ) <aaronbabb&gmail,com> on Monday January 19, 2004 @11:42PM (#8028353) Homepage
      A couple things:

      1. Writing those "ten lines of perl" is indeed worth it if you want the addresses from the site doing the obfuscation, especially if you know something about those contributing to the site and want to target particular types of people (probably not done often by spammers as they obviously prefer the shotgun approach). Spamming is a business and they can afford to pay programmers - and they DO, given that there are companies out there making software to service spammers.

      2. If the obfuscation is automatic or defaults to "on" there really is no message being sent by the owner of the address.

      I leave my address open (here and elsewhere) for two reasons: I don't really care what drops into that particular inbox and there's enough filtering on it, local and remote, that it's still useful as an open contact point.

      • A few notes:
        since for now, very few people obscure the same way, those ten lines of perl actually are probably closer to 30, just to eliminate the creative obsc. that get done, it's not worth it.

        Should we all pick ONE true way to obscure, you can expect methods to defeat it to gain popularity.

        Recently there was another slashdot about why lots more random "legal" words were introduced in spam, and how it might affect bayes. Many replies correctly pointed out that a correct bayes(individual token lists for

    • Re:Because... (Score:4, Informative)

      by StenD ( 34260 ) on Tuesday January 20, 2004 @02:57AM (#8029319)
      Yes, but, for now at least, there are still plenty of addresses from people who don't spam-guard, enough that writing those 10 lines of perl isn't even really worth it.
      It isn't even necessary to obfuscate addresses to foil many spammers. I generally use email addresses of the format user+folder@domain, and virtually all spammers who harvest the address either spam userfolder@domain, or folder@domain. It's nice for spammers to identify themselves, while not obfuscating my email address.
    • Even more than that- writing those 10 lines of perl would hurt the spammer. Think of it this way- the odds of someone who goes to the trouble of obscurification buying something in spam is virtually nil- an order of magnitude less than those who don't. By not picking up those addresses, he's raising his reply rate and success rate, saving himself money.

      • Re:Because... (Score:3, Insightful)

        by Weh ( 219305 )
        I suspect that the email harvesters don't really care about the person behind the email address, all they want is lots of valid email addresses which they can sell to spammers.

        • Re:Because... (Score:2, Interesting)

          by larry bagina ( 561269 )
          there was a slsahdot article a couple weeks aback about an anti-spam group over in Europe that bought a CD of email addresses to analyze it. They found a lot of duplicates, a lot of invalid (as in not legal format) addresses, a lot of ed@myNOSPAMsite.com obfuscication, and postmaster@127.0.0.1. Whether tha address is valid isn't even a concern for harvesters, apparrently.

    • Re:Because... (Score:4, Interesting)

      by ptomblin ( 1378 ) <ptomblin@xcski.com> on Tuesday January 20, 2004 @02:53PM (#8034345) Homepage Journal
      isn't even really worth it

      You know, if spammers cared a whit about anything except getting more addresses onto their "10 million email addresses" CDs that they sell by spamming, that would have some validity. However experience tells me otherwise.

      Spammers have hit email addresses that have only ever been used in postings in news.admin.net-abuse.email. They also spam my abuse@ email addresses. If there is any group of people more likely to have heavy spam filters and/or to complain or retaliate against spammers, it would be the people who post to n.a.n-a.e, and the people who handle spam abuse complaints for their domain. You'd think out of sheer self-preservation that spammers wouldn't bother those people, but they do.

  • slashdot@davidcole.net (Score:5, Informative)

    by DavidCole ( 534869 ) on Monday January 19, 2004 @11:33PM (#8028298) Homepage Journal
    What I usually do is, whenever possible, to put who I'm giving my email address to as the initial part of the email address, ie. slashdot@davidcole.net so I will at least know who the jerk is who sold my address.

    Otherwise, I use a hotmail account to commonly give out. Obfuscated email addresses are obnoxious.
    • If you used slashdot@davidcole.net, and got e-mail to that address, how would you know whether slashdot sold the address, or whether someone figured it out from the obfuscated address (if you actually used them that is)?
      • Doesn't really matter. The point is, you block the poisoned address and go to the next one. That's why there's a 2 in my address here - I once got a spam to the "slashdot" address. That's probably a few years ago, now. Nothing to this one, yet.
        • The problem with any site where the email address is publicly viewable is that it is harvested by bots. As per my own similar experience, I think that somewhere a spammer rubs his/her hands in glee every time somebody uses an unobfuscated slashdot email.

    • I will at least know who the jerk is who sold my address.

      Or the jerk who posted it in their slashdot post :)

      .02

      cLive ;-)

      ps - change your sig - or pay your bill! ;-)

    • Out of interest, have you received spam courtesy of any site/company that is newsworthy? I wonder how many of these larger "legit" sites/companies give out our email addresses.

  • Are firewalls worth it? (Score:4, Interesting)

    by anim8 ( 109631 ) on Monday January 19, 2004 @11:36PM (#8028313)
    So much energy is put into securing networks that ends up inconveniencing users while tons of exploits abound and social engineering completely bypasses it. Why bother?

    The reason people obscure their email is
    a) It's fast, easy and doesn't require external software.
    b) Sometimes that's all the protection you can get when you post to some sites.

    Nothing wrong here. Web utilization is still high. It's the spam that is the problem -- not the countermeasures.

  • 10 Lines? (Score:5, Insightful)

    by swdunlop ( 103066 ) <swdunlop AT gmail DOT com> on Monday January 19, 2004 @11:38PM (#8028323) Homepage
    Cool.. So, what ten lines do you recommend?

    Give us 10 lines of perl that will harvest armored email accounts out of a large document, with at least half of the harvested addresses actually usable, and at least half of the potential addresses harvested.

    The point is to make the harvesting costly, and reduce the usefulness of spam address harvesting. I maintain three email accounts. One that is used publicly, like here on Slashdot, one that is used for business transactions, like ordering things from Amazon, etc, and one that is a throwaway for registering accounts with various online services.

    Of the three, the first one, which is displayed widely, on K5, Slashdot, Groklaw, LiveJournal, and a lot of other heavily trafficed community sites, does not receive any spam of note. The second gets a pretty steady flow.. And the third.. Well.. The third is redirected to /dev/null most days, unless I'm looking for one of those precious "email validation" messages.

    Btw, that first email address has been in use for over three years, now.
    • Interestingly, I get more spam to my business account (unpublished, but guessable address sales@, support@, etc..) - than I do to any of my other email addresses, even my "throw away" ones.

    • Re:10 Lines? (Score:5, Insightful)

      by daviddennis ( 10926 ) <david@amazing.com> on Tuesday January 20, 2004 @12:07AM (#8028529) Homepage
      I could picture someone writing a truly humungous program to get all known variations. You could get one or two variations with 10 lines of Perl, but there are hundreds of different NOSPAM schemes out there, and each one would need a few lines to parse.

      davidNOSPAM@amazing.com
      david at amazing.com
      davidATamazingDOTcom
      david@amazing.M OC (with verbal instructions to reverse it)
      etc

      I don't bother spamguarding my address because I like to make it easy for people to contact me, and because my email address, in use since 1993, is pretty much everywhere anyway.

      Quite honestly postal spam bothers me more than email, since I have to physically dispose of it all ...

      D
      • Being able to harvest /all/ of it is not the point; the important thing is to be able to harvest a reasonable amount of it with your effort you put in. Just doing this will give me a reasonable amount from /.:

        s/[\`\'\"]//g;
        s/[\-\_\s]*nospam[\-\_\s]*//gi;
        s/\s+at\s+/@/i;
        s/\s+dot\s+/\./gi;
        s/([\@\.])+/ $1/g;

        I don't claim to know regex, and I had four beers. (No, it didn't take me one beer for each line *grin*) I am sure a lot of you out there can do a lot better than I did. But the point is, if I can g
      • Quite honestly postal spam bothers me more than email, since I have to physically dispose of it all ...

        The way I deal with that is to play thier own system against them. It works best if you get quite a few with prepaid return envelopes - save up a pile of them and then go through mixing up replies. Don't fill anything in, just put some of the junk one firm sent you in the prepaid envelope for the other. And if you have any newspaper spare, fold up some sheets of that and include it, anything to increase

        • Re:Postal spam tip (Score:2, Interesting)

          by w9wi ( 162482 )
          This unfortunately doesn't work to stop the postal spam. On the other hand, it does ensure that the spammer pays the cost of disposing of their garbage, not you. Your property taxes should pay for the disposal of the garbage you generate - let the spammers pay the taxes to dispose of their garbage.

          I don't bother waiting for prepaid envelopes to show up - any garbage postal spammers dump in my mailbox immediately gets "RETURN TO SENDER" written on it & dumped back in the mailbox. You need to mark out
        • My dad once had a magazine subscription that he wanted to cancel. He asked them to cancel, but they kept sending him stuff, so he took one of the business reply cards, and taped it to a big box of dirt (about 50 pounds or so) along with a letter saying please remove me, and sent it to them. He never got any more magazines.
      • Quite honestly postal spam bothers me more than email, since I have to physically dispose of it all ...


        Yeah, but at least postal spam costs the sender money, email spam costs your ISP bandwidth, and despite what anyone will tell you, bandwidth is NOT cheap.

    • Of the three, the first one, which is displayed widely, on K5, Slashdot, Groklaw, LiveJournal

      I recently received spam at the address displayed on /. It is an absolute rarity and I was surprised till I realized that /. users are a distinct demographic with certain common traits.

      For a business targeting the /. demographic it is probably worthwhile to get all the email addresses (easy to detect where they are on a page and about 750,000 maximum) and then run them thru iterative cleaning. In the first

      • Excellent point; the Slashdot demographic is pretty narrowly focussed, compared to the market at large, and, as such, is extremely valuable for a someone targeting that demographic. Unfortunately, as another poster mentioned, they tend to be predispositioned against spam. I'd like to think that more people in the /. community are less likely to fall for the Niagra scam than your average bumpkin.

        Then again, when I start making optimistic guesses about /. readers, some silly new fad starts up (Russia, fp's
      • I recently received spam at the address displayed on /. It is an absolute rarity...

        Well, then we can establish that address mangling works.

        I leave a contact address in unobscured text, and in the past 24 hours, I received 74 emails to that mailbox, all of which were spam.

    • Re:10 Lines? (Score:5, Funny)

      by ThenAgain ( 627263 ) on Tuesday January 20, 2004 @02:22AM (#8029189)
      Cool.. So, what ten lines do you recommend?

      Here it is in nine:

      #! /usr/bin/perl

      while(<>) { while(/([a-z0-9]+\@[a-z0-9.]+\.(com|org|net))/gi) { $a = $1;
      $a =~ s/[A-Z]+[0-9]*[A-Z]*//;
      print("$a\n");
      } while(/([a-z0-9]+ at ([a-z0-9]+ dot)+ (com|org|net))/gi) { $a = $1;
      $a =~ s/ at /\@/i;
      $a =~ s/ dot /\./ig;
      print("$a\n"); } }

      A real Perl hacker could probly do it in three, in the shape of a camel.

    • Re:10 Lines? (Score:4, Informative)

      by agwis ( 690872 ) on Tuesday January 20, 2004 @02:36AM (#8029254)

      "unless I'm looking for one of those precious "email validation" messages."

      A bit off topic but I found a cool site that handles those email validation messages you need to get once in awhile. It's called mailinator [mailinator.com]. Anytime you want to register with a site that asks for your email address so they can send you a validation code (and inevitably spam you to death) you can use mailinator's service for free. All you have to do is write bobs_your_uncle@mailinator.com and then you can login into that account at mailinator. All messages received there get deleted in a few minutes and do note that anyone else can access it as well, but it certainly is a good service to handle for that exact case you mention!

      -Pat

  • According to this it works... (Score:5, Interesting)

    by Nemozob ( 654510 ) on Monday January 19, 2004 @11:40PM (#8028336)
    A study [cdt.org] by the Center for Democracy & Technology in 2002 concluded that by either replacing email addresses with the HTML equivalent or human-readable equivalents like "example at domain dot com" signficantly cut down on spam. From their Major Findings: "E-mail addresses posted to Web sites using these conventions did not receive any spam." While, yes, it's relativley easy to write a script that would recombine the addresses, apparenlty most harvesters for whatever reason just aren't. My email address, which is posted online, is 'hidden' in HTML and I get very little spam after many years of having it up.

  • Harvesting addresses is like picking cotton. (Score:5, Interesting)

    by Anaxagor ( 211917 ) on Monday January 19, 2004 @11:40PM (#8028337)
    Go have a look around cotton fields just after harvest. Literally tons of the stuff is left behind at the edges of fields, blown along the roadside, lying on the stubble etc. Sure, you could go along and pick it up but the cost of doing so would outweigh the price you'd get for the extra x bushels you'd collect.

    It's the same with e-mail addresses - why should a spammer go to the trouble of modifying their bots to detect obscured addresses, when there are plenty of unobscured ones ready for harvest?

    I'm sure some spammers do try to pick up obscured addresses, but until they start running out of unobscured addresses, they'll keep going for the masses of low hanging fruit and not bother with the rest.

    Of course, obscurity doesn't save your address from brute forcing...

  • try this (Score:4, Insightful)

    by Joe the Lesser ( 533425 ) on Monday January 19, 2004 @11:41PM (#8028349) Homepage Journal
    email:(Thecapitalofnewyorkstate)354@hotmail.com.fi llintheblank.

    no program is gonna figure it out, unless they knew the algorithm, which they likely don't. It's always *possible* to outmanuever the spammers in some way or another.

    Whether it's worth the hassle, is of course, your call.

    (albany354@hotmail.com is not my actual email address, so feel free to spam it.)
    • Another usefull obfuscation is something like @my.domain.blah.foo.tld. That 10 lines of perl would need to do some serious mx lookups to figure out the real address and that would usually cost some real time when parsing gazilion of obfuscated addresses.

    • Re:try this (Score:3, Insightful)

      by Craigj0 ( 10745 )
      >email:(Thecapitalofnewyorkstate)354@hotmail.com.f i llintheblank.
      >no program is gonna figure it out, unless they knew the algorithm, which they likely don't. It's always *possible* to outmanuever the spammers in some way or another.
      >Whether it's worth the hassle, is of course, your call.

      Remember it is not just a hassle for the creator of the email address. It is also a pain in the ass for everyone else. I for one hope I never have to send an email to someone doing that type of masking. How many

  • Definitely Worth It (Score:5, Interesting)

    by jmt9581 ( 554192 ) on Monday January 19, 2004 @11:45PM (#8028380) Homepage
    I think that it's definitely worth it. There's no standard way of obfuscating the address. Because TIMTOWTDI, your ten-line Perl script either
    • Gets very complex very quickly
    • Doesn't correctly un-obfuscate every address

    For example, while you might post your address as:
    user@NOSPAM.domain.com
    I may post mine as
    user2@no_spam_damnit.domain.com
    To me, using relatively simple tricks like this to make the job of a spammer harder is definitely worthwile.

    • This is interesting. I have occasionally gotten spam offering email addresses. They're sorted by domain, have duplicates removed, and also have had addresses removed which contain certain strings such as "spam", as such addresses are generally not real ones - like yours.

      Double protection is good, but some people just don't get it, especially when you post in places such as newsgroups, where you've modified your from address. I've wondered whether setting up a real subdomain for real email addresses woul

  • spamcop.net makes me feel good (Score:3, Insightful)

    by njchick ( 611256 ) on Monday January 19, 2004 @11:57PM (#8028449) Journal
    I don't obscure my e-mail address. My e-mail is filtered by spamcop.net [spamcop.net]. All the spam sent to me gets reported without taking too much of my time. It's the feeling that I fight spammers rather than hide from them that makes me feel good. The filtering costs $30 a year, and it's an excellent value. No, I'm not affiliated with spamcop.net in any other way.

    My less technical friends have no problem mailing me because I use a mailto link on my homepage.

    I use a separate yahoo address for shopping. I don't want my shopping information to be linked to my personal website. The spam from the yahoo address is also fed to spamcop.net. Sometimes I also use one-time hotmail addresses to buy from dealers with high spam risk. I simply stop using those accounts and forget the password once the transaction is complete.

    • My less technical friends have no problem mailing me because I use a mailto link on my homepage.

      I have a link too, but I use &#64; instead of @ and that actually works well enough that spam bots don't recognise it. The browersers I've tried (Konq,Moz,IE) display it and handle it properly though. I saw that here a while back in an article about where addresses are most likely to be harvested from.

      -- Steve

    • an even easier way to get one-time email addresses is spamgourmet.com. you don't have to go to their website more than the once to register. after that, just make up an address and they will forward it to you a limited number of times.

      for example, the first 4 messages sent to slashjunk.4.mbloore@spamgourmet.com will be forwarded to me; any more will be eaten.

      more control is available if you want it, such as whitelists and resetting the count. and you can reply throgh them, so your forwarding address is

  • My technique... (Score:5, Funny)

    by Txiasaeia ( 581598 ) on Tuesday January 20, 2004 @12:00AM (#8028473)
    ...is to make an address completely unreadable to anybody but a human. For example:

    kajohnson@hotmail.com BECOMES
    kay_a_sonofjohn_atuh_hawtmayled0tcawm_(first_word_ letter_second_word_letter_switchfifthandthird_word _getridof_of_restofaddress_is_phoenetic)

    Sure, it's brutal to decipher, but there's no way a machine can poke through that mess. Fun for the receiver to figure out too :)

  • Worst of two evils (Score:5, Informative)

    by Nucleon500 ( 628631 ) <tcfelker@example.com> on Tuesday January 20, 2004 @12:22AM (#8028615) Homepage
    The cost in terms of usability of munging adresses is too high. There are better ways to fight spam.

    For me at the moment, Bayesian filters, a technical solution, works best. Yes, it still wastes bandwidth. But if my ISP ran good filters for me (POPFile [sf.net] is adapting itself for this usage), my bandwidth at least could be saved. And the filters do work well.

    Technical solutions are a stopgap measure, but the next step is legal and architectural. Make spamming illegal. This would only affect countries that care and spammers who get caught, but the next step will help. Make it harder to hide where you're coming from. This gives even ISPs in lawless countries motivation to stop sending spam, because if their upstream knows its them, they can threaten to disconnect them.

    Munging is probably the worst solution, similar to getting an unlisted number. It's even shorter-term than filters, but it sacrifices the medium in the process. It's a bit like not answering the phone during mealtime - yes, it works, but it interferes too much with legitimate communication. If that's your choice, fine, but I think its ill-advised.

  • Future solution... (Score:2, Interesting)

    by r00k123 ( 588214 )
    Say someone does come along and writes some code to get at "armored" addresses. What do we use then?

    How bout your email address displayed as a small image?

    Yahoo and other sites have been using words in an image as an anti-automated-signup with good success. They work because it's just too hard to get text out of a fuzzy/obscured image automagically. Image recognition simply isn't good enough yet.

    Definite overkill now, but spammers are always cracking the latest line of defense...

    • >How bout your email address displayed as a small image?

      That's annoying to people who legitimately want to send you an email.

    • Re:Future solution... (Score:2, Insightful)

      by Grhm ( 600969 )
      If you start hiding your email address in blurred or obsured images, you also end up pissing of those with poor eyesight.

      My dad can read email and surf fine without his glasses but sometimes he has to go get his glasses to work out what the "anti-automated-signup" image says.

  • To answer your question: yes of course it's worth it. It take 3 seconds and befuddles every current email spider on the web.

    Sure, ten lines of perl code could decode any ONE technique on Slashdot, but it would take much more to detect which technique (of infinite possible) was used.

    However, there is a situation where it becomes reasonable to use such a descrambler. On some mailing list archives, there is a standard anti-spam format applied to every email address. In this case, picking one lock would

  • My sig (Score:3, Interesting)

    by Durin_Deathless ( 668544 ) on Tuesday January 20, 2004 @01:13AM (#8028883) Homepage
    I have been TRYING to get spam to test out the settings on my spamassasin install. I can't do it. I have had the unarmored address in my sig, and it gets NOTHING! I have never been annoyed about a lack of spam before.

    spam@tuxserver.ath.cx
    It's down now though. Server lost a hard disk overnight. Stupid thing.
    spam@tuxserver.ath.cx --I WANT SPAM!!!!

    • Re:My sig (Score:3, Insightful)

      by Lukey Boy ( 16717 )
      Maybe the bots filter the word spam.
      • Yeah, i'd bet they would... although people say they get spam on spamcop addresses (i'm not sure exactly how spamcop works, but i think you can get toast0@spamcop.net or forward slashdot@enslaves.us to them)

    • I have had the unarmored address in my sig, and it gets NOTHING!

      Try using it to register a domain name. I use domains at littlecutie dot net for nothing -- absolutely nothing -- but domain registrations. I cleaned it out last week, and it now has 162 messages. One is a renewal notice on a domain. The rest are spam.

      I may change my domain registration email to domspam at littlecutie dot net and see what happens, though!
    • Do a Google search on somehting like "XXX teen sluts" and enter your email address at the first ten sites. You'll have all the spam you need. If you want to manually train Spamassassin, then try usenet: news.admin.net-abuse.sightings
  • It does seem strange that address obfuscation works at all. As ThenAgain points out, it doesn't take that must code to turn "dubya(at)whitehouse.gov" into "dubya@whitehouse.gov" (oops!).

    And yet obfuscation seems to work quite well, at least in my experience. How can this be?

    I can think of two big reasons. The first is that deobfuscation is harder than it looks. It's not just a matter of applying the reveral -- you also need to recognize which reversal to supply (dubyaNOSPAMwhitehouseNONEgov, dubya at wh

  • Brains, not gibberish (Score:4, Interesting)

    by ezraekman ( 650090 ) on Tuesday January 20, 2004 @01:23AM (#8028928) Homepage

    Step 1
    Register your own domain name. Cheapest reliable registrar I'm aware of is Godaddy [godaddy.com], at about eight bucks a year per domain for .com, .net and .org TLDs, more/less for others. (Five bucks a year for ".us", for example.) Having trouble picking one? Use your own name, or add "bork" to the end or something. It really isn't that big a deal.

    Step 2
    Permanently disable the following addresses: info@, support@, webmaster@, ceo@, sales@, president@, admin@, contact@, customerservice@, and tech@.

    Step 3
    Can you figure it out by my e-mail address? If not, shoot me one, I'll I'll clue you in, if you can demonstrate that you're not a spammer. ;-) Here's a hint: You'll your host to support this mail feature.

    Step 4
    Don't post your address, genius! If you slap your e-mail address on a website, in a mailing list, etc... you're gonna get spam. That's the way it is. Stop whining about it, and figure out a solution. (See step three.) If you haven't figured out step three yet, e-mail me.

    Step 5
    Pay attention. Think about who you give your address to. This goes for the address you use for your domain registration. Oh, and register your domain with an address that you don't care about getting spam at. A month or two later, change it. Spammers pay more attention to the e-mail address a domain is registered with than they do the address(es) that it ends up with later.

    I own about twenty domain names, and use multiple addresses for each domain name. I get a combined total of about 3-10 spams per day, tops... and those are only to the addresses I was using before I developed these rules. The benefits? Little to no spam, you can track every company that's sold or shared your information, and easily see who violated their privacy policy. Then, of course, you just shut down the spam that they've enabled, and go on as usual.

    It works.

  • Server side scripting (Score:3, Insightful)

    by mikeswi ( 658619 ) * on Tuesday January 20, 2004 @01:24AM (#8028937) Homepage Journal

    I don't obfuscate at all. I use a server side script to generate a form. The client (browser, spambot, whoever) never sees the address. It is not possible to figure out the address, no matter how determined the spammer is.

    I VERY HIGHLY recommend this free php or asp email form [dbmasters.net].

  • Regardless of "could", they apparently haven't been written.

    "So if we're not helping hold back the flood of spam..."

    We who? I get zero. Not bad for 1,320 web hits on Google on my last name, and over 12 years of regular usenet use. And I do NOT filter. I'm just careful.

  • Seems to have worked for me. The only email address used for /., LJ, and any online signups is thisismyspamdump@. I've never had a spam on this address, mind you, it's only been 6 months :)

  • Think out of the box (Score:3, Insightful)

    by Kris_J ( 10111 ) * on Tuesday January 20, 2004 @02:43AM (#8029281) Homepage Journal
    Given that inserting the word "SPAM" into an email address is a typical way of attempting to block spam, such that email harvesters might remove the word "SPAM", the trick is to have an email address that legitimately contains the word SPAM, preferably after the @, such that email harvesters bugger up the address. Spamcop.net and Spamgourmet.com both offer this feature. Makes life even harder for the little bots if you put a "NO" before the "SPAM", eg: blah@NOSPAMcop.net, then include a human readable "my address has no no in it".

  • Ten lines of Perl? (Score:4, Interesting)

    by dbirchall ( 191839 ) on Tuesday January 20, 2004 @04:20AM (#8029634) Journal
    Geez... doesn't take more'n about 3 lines to do this as "bin.cgi":

    #!/usr/bin/perl
    print "Location: mailto:dan@sales.example.com\n\n";
    exit(0);

    And then it's just a simple matter of replacing:

    a href="mailto:dan@sales.example.com"

    with:

    a href="/bin.cgi?href=mailto:abuse"

    I've been doing this type of thing since about 1998. Surprised more people don't do it. It's fairly trivial to improve upon it and add quasirandom munging to the addresses, etc...

    • Um, no. He means ten lines of perl will un-mangle "user AT mikerowsoft DOT com" or other, as you put it, "quasirandom munging."
      • My definition of "quasirandom" is pretty far beyond "AT" and "DOT." ;)

        Of course, the sole Slashdotter who wants to de-munge addresses on a site of mine will go to the trouble of figuring out how the quasirandom munging works, for that one site.

        Figuring out different quasirandom munging for a large number of sites, though -- which is what address harvesters would have to do -- would be about as big a task as figuring out how to pattern-match spam 100% of the time.

        Especially if the munge kept mutatin

    • The problem with that is that it assumes that the user's mail client is on the same machine as their web browser. I don't have an email client on my machine. I ssh into my server and use mutt. Your method makes it difficult to copy your email address, or just read it from the screen, and put it into mutt.

  • Yes, trivial obscuring like user(at)example(dot)com with various special characters can be done in 10 lines. (Could be hard to get the last 3 lines filled with code.)

    But what if the user does not use English language, but German? And what if (s)he does not mark the obscured charachters? user klammeraffe example punkt com or with some funny synonymes user a im kringel example klecks com. Decoding this in 10 lines of Perl becomes harder, and it becomes harder with every new language. Decode this with 10 lines for English, German, French, Polish, Russian, Bantu, Spanish, ...

    What happens if the user is really "evil" to spammers? Meine Mail-Adresse besteht aus dem Domainnamen meines Providers example unter der Top-Level-Domain fur kommerzielle Webseiten, dem wird mein Kundenpseudonym user und ein Klammeraffe vorangestellt. (I'm still hiding user@example.com - translation: My mail address is composed from the domain name of my provider example undet the top level domain for commercial websites, prefixed with my client pseudonym user and an at sign.) Decode this and similar examples in 10 lines of Perl for 10 languages, while still being able do decode all trivial variants and all slashdot mail obscurations.

    Getting more evil: Meine e-Mail ist catch-those-spammers@example.com [mailto] mit user vor dem Klammeraffen. Schicken Sie keine Mails an die falsche Adresse. (My email is catch-those-spammers@example.com with user in front of the at sign. Don't send mail to the wrong address.) Set up an account catch-those-spammers that marks and blocks all computers that test that acocunt or send mail to it. Now decode this and all examples above and all slashdot obscuration and don't run into the trap, and do not use more than 10 lines (with 80 characters each) of Perl code.

    I bet it can't be done in 10 lines with 80 characters each, using Perl 5 and no external modules.

    With nearly no work it is possible to make automatic address collecting harder and thus more expensive. Spammers don't want to spend much money, they want to maximise their profit. So they will do at most only trivial decoding, if they can't collect enough unobscured mail adresses. This is why images containing the mail address won't be OCRed for a while. It simply costs too much. On the other hand, just guessing names for existing domains works pretty well and it is very cheap. I have an unpublished six-letter account at a big German mail provider, and it is permanently hit by spam. The generic (unused and unpublished) accounts (sales, info, mail, accounting, vertrieb) of my domain are also spammed very often. Guessing is cheaper than collecting addresses.

    So while this is not a mathematical proof, you can see that non-trivial obscuration will help. See also What You Get When You Buy a Spam CD [slashdot.org].

    Tux2000

  • Since I switched to OSX and started to use Mail.app I've found the adaptive junk mail filters to be quite good. Plus the ability to bounce spam makes those spamers who actually maintain their lists remove my name automatically. I've left Mail in the learn mode so that I can declare a spam to be junk if it gets past the filter. I have also made a separate filter for mail marked as junk, so after glancing to make sure that it is indeed junk I bounce it. I get fewer and fewer junk mail each passing day. I
    • Does it actually cause a server (never played with Mail.app) to bounce the message with a proper 550 or similar, or just reply with a form?

      There was some discussion on /. a while ago about doing spam filtering during the transaction phase on the MTA, allowing you to really bounce messages (at the risk of false positives.)
      • Well, it has some caveats during the bounce. The biggest one, which makes it useless to me, is that it bounces with your primary email address, regardless of who the email was sent to. Since the email addresses I receive spam on are not my primary address, bounces really wouldn't help.

        (That is, my primary address may be 'foo@bar.com', but I receive spam on 'baz@bat.com'. If I generate a bounce message from that spam, the bounce will include 'foo@bar.com' as my address.)

        Luckily, SpamAssassin gets almost al
    • I too use Mail and use the junk mail filters. I have noticed that spam is starting to get through. Apparently its a new kind of spam message that contains a list of words to get through filters?

      Also, when my business partner forwards email to me, it often marks it as Spam for some reason. Like sometimes he forwards info off of a web page that is advertising something he wants me to look at.

  • I don't even bother obscuring my address most of the time due to a handy free (as in beer and speech) little utility over at Spamgourmet.com [spamgourmet.com]. It allows you infinite disposable email addresses that forwards to an address you specify.

    How it works: When some site/etc is asking for your email address and you just *know* they're going to spam you, give them a spamgourmet address. -

    identifier.#ofemailstoaccept.userhandle@spamgour met.com

    I.E.

    slashdot.5.user@spamgourmet.net

    Once you get five emails you wo

  • Sure, using YoureAllWrong(at)yahoo(dot)com is trivial to detect, but there are an infinite number of schemata that can be used. Just use your imagination.

    YAW.

  • Use subdomains if possible... (Score:4, Interesting)

    by DocSnyder ( 10755 ) on Tuesday January 20, 2004 @07:42AM (#8030365)
    For my Usenet and Web forum activities, I'm using unmunged email addresses with "temporary" subdomains, e. g. "slashdot@expires-200401.docsnyder.de" [docsnyder.de]. After some time I will deactivate them in my DNS - they no longer exist, neither do their MX records. Except for a few DNS queries, spammers don't even cost me any significant network traffic - they don't find my email server!

    Of course it's some work changing email addresses after expiration (I'm rotating most of them after three months), but it's less work then eating all their spam.

  • I've seen /. use things like "daniRABBITel@franke.name minus herbivore". That's obviously going to be virtually impossible for spammers to crack.
    • ah yes

      jeff@FUCKSPAM.hotmail.com
      bNOoSPAMb@blah.SPAM.c om

      etc etc.

      Has it occured to anyone that if you start using CAPITAL LETTERS to distinguish noise from signal then that's reasonably easy to filter out?

      Eeh, good on you for making the effort, but you probably do want some viagra anyway, you're just shy. The best obfuscation is to use a suitably noised up image but that presents problems of its own...

  • It's the same as encrypting your WiFi, etc (Score:3, Interesting)

    by chia_monkey ( 593501 ) on Tuesday January 20, 2004 @10:11AM (#8031255) Journal
    Why do that to our email addresses? Because it actually DOES help a little bit. Why lock our doors at night? Why lock our car when we park downtown? Why encrypt our WiFi network? Why install SOME sort of security on our network? Because we don't want to make it blatantly easy for someone to compromise. If someone really wants that car, they'll get it. If someone really wants to break into your network, they'll do it. But this is one easy level of "security" that will stop the basic script kiddies/thieves/spammers from doing all the damage they want. It may not be the most effective way of stopping spam, but why put a sign on your car (or website) that says "hey, I'm unlocked and the keys are in the ignition"?

  • The CLUB (Score:2, Interesting)

    by jmlyle ( 512574 )
    It's like the CLUB, the automotive theft prevention device (A club that locks accross the steering wheel). By no means could the CLUB prevent someone from stealing a car that they wanted to steal, but if there are two cars next to each other, one with a CLUB and one without, the non-CLUB car is more likely to be stolen.

    In effect, the advantage of the CLUB (and of obfuscating your email) is that you are protecting yourself simply because someone else hasn't put in the effort that you have. As long as enough
  • I obfuscate the contact address for my website with some javascript, and don't otherwise publicise it. No spam yet, and it's been available for a few months. Of course, no one really cares about my website anyway...

  • Personal experience (Score:3, Interesting)

    by phorm ( 591458 ) on Tuesday January 20, 2004 @12:44PM (#8032921) Journal
    The first time I got an article up on slashdot, the associated email was non-obfuscated.
    I knew the article was posted before I even checked /., due to a sudden deluge of spam going to the alias linked in the article.

    The second article I had posted, I obfuscated my address. Thus far no spambots have managed to hit me on that alias.

    I'd say that the obfuscation definately worked in this case. It wouldn't fool a spammer doing a visual search for victims, but it was enough to trick the bots.

    I wonder though, if slashdot (being very anti-spam) is given special attention by spammers... or if it just goes along with being a highly popular website and thus a good place to harvest addresses.

  • Simple and effective obfuscation (Score:3, Informative)

    by hankwang ( 413283 ) * on Tuesday January 20, 2004 @05:04PM (#8035844) Homepage
    These tactics work and do not require to much thinking/demunging by the user:
    • Replace @ by &#64; (sounds simple, but it is reported to work - so far)
    • Make mailto links in javascript (Spambots don't appear to parse javascript so far)
    • Make a CGI that serves the email address in a clickable form after the user presses a button. Spambots don't parse HTML forms - yet. Use POST instead of GET such that there does not exist any URL that will serve the email address. Optionally include a simple question in the form. (I implemented:

      Email address of John Doe
      I am: (x) a robot; ( ) a human [GET EMAIL ADDRESS]

      on a website. (Answering wrong will give you 1000 nonexisting email addresses :-) ) If you suspect that the spammer might want to invest some time in writing a script that harvests all 20000 employees from your website, then make it a Kaptcha (type the digits in the image into the box).

    Having to demunge an address is annoying. How many spaces do I have to remove from jl i11@example .com? Did I place the cursor left or right of the whitespace? Damn, one space too many removed.

    Spambots are stupid. I've seen a few of them visit a website that I maintain and they do not even parse basic HTML such as the BASE tag (which the parser needs to derive relative URLs), or the presence of &amp; in URLs (HTML does officially not allow bare & symbols).

  • I know this because I see failed attempts in my maillogs, like:

    some_removethis_body@example.com

    wrongly deobfuscated to

    some__body@example.com

  • A lot of spammers are not selling anything besides their spamming services.

    They say they will "send your message to 10 million gazillion users" but do they really care that a lot of the addresses they send to are dead, abandoned or obfuscated?

    No, they just have a bunch of addresses, and as long as it is in the form of foo@bar.com they don't care if it bounces back, it is still valid enough for their customers.

    Remember, it is spammers that we are talking about here. [pennypacker.org]

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