Slashdot Mirror
Stopping Spambots: A Spambot Trap
Neil Gunton writes "Having been hit by a load of spambots on my community site, I decided to write a Spambot Trap which uses Linux, Apache, mod_perl, MySQL, ipchains and Embperl to quickly block spambots that fall into the trap. "
Looking at my Day Job and personal web site, other than the very cool technical achievement of the trap (I'll have to see if I can rewrite this for my Checkpoint FW system), there were one things I learned about good design from this article:
Eliminate mailto - makes sense. You should have an http based "send me a message system" - force a live person to type stuff in instead of letting a program pick out addresses.
Eliminating mailto alone would probably help in mot of my spam problems (as I have my "contact me" address right on the first page).
52 Weeks, 52 Religions with John Hummel
Looks like you should've written some code to handle an overload from slashdot too!
"I have a truly marvelous demonstration of this proposition which this bandwidth is too narrow to transmit."
www.timcoleman.com is a total waste of your time. Never go there.
Why on Earth would you like to block a spambot? So it doesn't get any more useful addresses? /give/ it a next page. With a nicely formatted word1word2num1num2@word1word2.com, where words and nums are random.
No way, man.
If you realize you're serving to a bot, go on serving. Each time the bot follows the "next page" link, you
Give it thousands, millions of addresses this way.
hmm, just a wild guess, but does this technique involve using the http-referrer to see if there are too many clients coming from just a particalar address (which would obviously be a *bad* thingy), and subsequently block them too?
might explain why we can't see it no more
I want it too!!! it seems to work pretty good!
As it turns out, I really haven't received that much mail to this address. About the only mail I've ever received to it is someone from trafficmagnet.net, who tells me that I'm not listed on a few search engines and that I can pay them to have my site listed. I need to send her a nasty reply saying that I don't care about being listed on Bob's Pay-Per-Click Search Engine, and that if she had actually read the page, she would have noticed that she was sending mail to an invalid address. Besides, the web server is for my inline skate club and we don't have a $10/month budget to pay for search engine placement.
I think I've received more spam from my Usenet posting history, from my other web site, and from my WHOIS registrations than I've received from the skate club web site.
From the website:
The Problem: Spambots Ate My Website
s/Spambots/Slashdot/
My PHP spider-trap - See an infinity of email addresses and links in action!
The only problem with the idea of using entirely http based "send me a message systems" is that some people, like myself, would much rather have an actual email address to use instead of having to use 50 different layouts and 50 different configurations and 50 different methods of communicating with someone or a company. Every html based contact system has its own quirks and problems, I'd rather just need to learn my email programs issues instead.
Removing mailto: links is a bad solution to the problem. It might be the only solution, but it is bad.
I hate the editor in my web browser. No spell check (and a quick read of this message will prove who diasterious that is to me), not good editing ability, and other problems. By contrast my email client has an excellent editor, and a spell checker. Let me pull up a real mail client when I want to send email, please!
In addition, I want people to contact me, and not everyone is computer literate. I hang out in antique iron groups, I expect people there to be up on the latest in hot tube ignition technology, not computer technology. To many of them computers are just a tool, and they don't have time to learn all the tricks to make it work, they just learn enough to make it do what they want, and then ignore the rest. Clicking on a mailto: link is easy and does the right thing. Opening up a mail client, and typing in some address is error prone at best.
Removing mailto: links might be the only solution, but I hope not. So I make sure to regualrly use spamcop.
This isn't such a good idea - for every random (non-existent) domain that you generate, a root DNS server will be queried when an email is sent to this address, which increases the load on the root servers, which is generally a bad thing. How about instead, returning pages with the email address abuse@domain-that-spambot-is-coming-from all over them...
After the Battle Creek incident with ORBZ, the maintain changed the way it worked; instead of being pro-active on checking for open relays, he now has a 'honeypot' like system where a unique email address that isn't directly visible on the site but still may be harvested by a spam bot. Any server that sends email to that address is automatically added to The List. Mail server admins that believe that they should not be on this list can argue their case to remove their server.
"Pinky, you've left the lens cap of your mind on again." - P&TB
"I can see my house from here!" - ST:
But, if you send him the message once with your return address, he'll know you're for real and when he replies you can use your regular mailer.
$0.02USD,
-l
Help cure AIDS, cancer, and more. Donate your unused computer time to worldcommunitygrid.org. Join Team Slashdot!
Superior Labs spambot_trap mirror
-Spack
Here's a tip for those of you writing spambot traps... How about not blindly responding to the faked Return-Path address?
Now that should be illegal. You people whine about your 10 spams a day, try 10,000 from 2000 different email addresses. Idiot postmasters should be caught and jailed.
formmail itself (even the most recent version) can still be abused by spammers to use your webserver as a bulk mail relay - see the advisory ato ry . df
http://www.monkeys.com/anti-spam/formmail-advis
It's a shame he didn't suggest the more robust formmail replacement at nms which is maintained, and attempts to close all the known bugs and insecurities.
Add a couple of sleep(20); into the cgi script that generates the bot fodder. The bot will still stay busy waiting for your webserver's response, but your script will exactly consume zero resources.
For additional kicks, set up a DNS teergrube.
Say no to software patents.
I've found that a lot of people just won't send email if there's not a link to facillitate it. I've become rather fond of using javascript to write the address to the page. Spambots read the source so they don't piece the address together but *most* browsers will still do it right. Just use something like:
<script>document.write("<A CLASS=\"link\" HREF=\"mailto: " + "myname" + String.FromCharCode(64) + "mydomain"</script>
Seems to work fine. Anyone know of any reason it shouldn't, or have any other way to keep down spam without totally removing the Mailto: ? I know this won't work with *every* browser, but it beats totally removing mail links. And I don't think spammers can get it without having a human actually look at the page...
do not read this line twice.
My setup (catches some of the more commonly used spambots) uses mod_rewrite to send spammers to a trap.
Setup details at http://www.bero.org/NoSpam/isp.php
This message is provided under the terms outlined at http://www.bero.org/terms.html
Have your page linked on slashdot! Page gets slashdotted, problem solved.
You can generate the code for your own email address here or, if you want some source code, then you can find an implementation of it here.
Avantslash - View Slashdot cleanly on your mobile phone.
1) Put a link such as: mailto:dedicatedaddress@wherever.com?Subject= [Question] About your site (or whatever)
2) Trash any email sent to dedicatedaddress that doesn't have the [Question] tag in the subject.
Hope this helps.
-- B.
This sig does in fact not have the property it claims not to have.
Why is this a bad thing? They are owned by Verisign.
How about instead, returning pages with the email address abuse@domain-that-spambot-is-coming-from all over them...
This is also a good idea. In fact, I have a script which does a traceroute to the IP of the bot, and then looks up the admin contact using whois for the last couple of hops, and returns these. Oh, and for additional fun, throw in a couple of addresses of especially loved "friends"...
Say no to software patents.
Write some of your email address using html code for the ascii characters, like $ # 114 for "r".
(Yes, I've posted about this before, but it does work for me.) Browsers render it so users get the address they want, but spambots try to grab it from the raw html and get something meaningless.
Add a couple of sleep(20); into the cgi script that generates the bot fodder. The bot will still stay busy waiting for your webserver's response, but your script will exactly consume zero resources.
Zero resources, except for memory.
A much better solution would be to point the bot at a set of "servers" with IP addresses where you're running a stateless tarpit.
Tarsnap: Online backups for the truly paranoid
The page is already slashdoted. Here is a little .htaccess file with mod_rewrite turned on
/dont_go_here /images /cgi-bin
R EMOTE_HOST);
script that traps bots (and others) that use your robots.txt
to find directories to look through. Requires an
robots.txt
#################
User-agent: *
Disallow:
Disallow:
Disallow:
dont_go_here/index.php
############
$now = date ("h:ia m/d/Y");
$IP=getenv(REMOTE_ADDR);
$host=getenv(
$your_email_address=you@whatever;
$ban_code =
"\n".
'# '."$host banned $now\n".
'RewriteCond %{REMOTE_ADDR} ^'."$IP\n".
'RewriteRule ^.*$ denied.html [L]'."\n\n";
$fp = fopen ("/path/to/.htaccess", "a");
fwrite($fp, $ban_code);
fclose ($fp);
mail("$your_email_address", "Spambot Whacked!", "$host banned $now\n");
AdFuel
From the website: Wpoison is a free tool that can be used to help reduce the problem of bulk junk e-mail on the Internet in general, and at sites using Wpoison in particular.
It solves the problems of trapped spambots sucking up massive bandwidth/CPU time, as well as sparing legitimate spiders (say, google) from severe confusion.
Actually, I've done this w/a bot trap on my site at home. It's a perl script that generates a bunch of weird-sounding text w/some fake email addresses at the bottom and a bunch of database-query-looking links back to the original page.
The bots don't fall for it anymore. Some dorks in Washington state decided to make a couple requests a second to it once, but in the two years I've had it up, they're the only ones.
A pretty good article, but being able to install modules into Apache may not be the best situation for everyone who wants to stop Spambots..
Shameless plug, but I've got an ongoing series in the Apache section of /. that deals with easy ways that administrators *and* regular users can keep Spambots off their sites:
Stopping Spambots with Apache
and
Stopping Spambots II - The Admin Strikes Back
Just some more options and choices to help people out!
I like that idea...look up the originating host, and make links back to abuse@, root@, webmaster@, and whatever else you can think of. Clog their mailservers. The problem is, it would be simple enough (if it's not already in place) to have your spam bot ignore addresses for your own domain.
do not read this line twice.
Give it thousands, millions of addresses this way.
Liberally sprinkled postmaster@127.0.0.1 and abuse]@127.0.0.1.
If you use images for email addresses, what are people using text browsers supposed to do? Even worse is using them on the "warning" pages - someone with a text browser would have no idea what the image said and therefore nothing to stop them falling into the trap and getting firewalled.
And of course if he uses ALT text for the images, then he has the same problem he was trying to avoid, of creating something the spambots can read.
I agree. And, come on, how much technology do you need?
This is my solution to stopping spambots. It's in a JavaServlet technology and I am posting it here to prevent my company's site from being slashdotted. It does not prevent the spammer from harvesting emails it just slows them down.... a lot :) If everyone had a script like this, spambots would be unusable.
Feel free to use the code in anyway you please (LGPL like and stuff)
Put robots.txt in your root folder. Content:
User-agent: *Disallow:
Put StopSpammersServlet.java in WEB-INF/classes/com/parsek/util:
package com.parsek.util;import java.io.File;
import java.io.StringWriter;
import javax.servlet.ServletContext;
import java.net.URL;
import java.util.Enumeration;
import java.lang.reflect.Array;
public class StopSpammersServlet extends javax.servlet.http.HttpServlet {
private static String[] names = { "root", "webmaster", "postmaster", "abuse", "abuse", "abuse", "bill", "john", "jane", "richard", "billy", "mike", "michelle", "george", "michael", "britney" };
private static String[] lasts = { "gates", "crystal", "fonda", "gere", "crystal", "scheffield", "douglas", "spears", "greene", "walker", "bush", "harisson" };
private String[] endns = new String[7];
private static long getNumberOfShashes(String path) {
int i = 1;
java.util.StringTokenizer st = new java.util.StringTokenizer(path, "/");
while(st.hasMoreTokens()) { i++; st.nextToken(); }
return(i);
}
public void doGet (javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
throws javax.servlet.ServletException, java.io.IOException {
response.setContentType("text/html; charset=UTF-8");
java.io.PrintWriter out = response.getWriter();
try {
ServletContext servletContext = getServletContext();
endns[0] = "localhost";
endns[1] = "127.0.0.1";
endns[2] = "2130706433";
endns[3] = "fbi.gov";
endns[4] = "whitehouse.gov";
endns[5] = request.getRemoteAddr();
endns[6] = request.getRemoteHost();
String query = request.getQueryString();
String path = request.getPathInfo();
out.println("<html>");
out.println("<head>");
out.println("<title>Members area</title>");
out.println("</head>");
out.println("<body>");
out.println("<p>Hello random visitor. There is a big chance you are a robot collecting mail addresses and have no place being here.");
out.println("Therefore you will get some random generated email addresses and some random links to follow endlessly.</p>");
out.println("<p>Please be aware that your IP has been logged and will be reported to proper authorities if required.</p>");
out.println("<p>Also note that browsing through the tree will get slower and slower and gradually stop you from spidering other sites.</p>");
response.flushBuffer();
long sleepTime = (long) Math.pow(3, getNumberOfShashes(path));
do {
String name = names[ (int) (Math.random() * Array.getLength(names)) ];
String last = lasts[ (int) (Math.random() * Array.getLength(lasts)) ];
String endn = endns[ (int) (Math.random() * Array.getLength(endns)) ];
String email= "";
double a = Math.random() * 15;
if(a if(a if(a if(a if(a if(a if(a if(a if(a if(a if(a if(a if(a email = email + "@" + endn;
out.print("<a href=\"mailto:" + email + "\">" + email + "</a><br>");
response.flushBuffer();
Thread.sleep(sleepTime);
} while (Math.random()
out.print("<br>");
do {
int a = (int) (Math.random() * 1000);
out.print("<a href=\"" + a + "/\">" + a + "</a> ");
Thread.sleep(sleepTime);
response.flushBuffer();
} while (Math.random() out.println("</body>");
out.println("</html>");
} catch (Exception e) {
out.write("<pre>");
out.write(e.getMessage());
e.printStackTrace(out);
out.write("</pre>");
}
out.close();
}
}
Put this in your WEB-INF/web.xml
<servlet><servlet-name>stopSpammers</servlet-name& gt;
<servlet-class>com.parsek.util.StopSpammersS ervlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>stopSpammers</servlet-name& gt;
<url-pattern>/members/*</url-pattern>
</servlet-mapping>
Here you go. No PHP, no APache, no mySQL, no Perl, just one servlet container.
Ciao
boky
However, the instructions for installating Wpoison more or less assumes that one has a single website to protect. I have around 20 virtual hosts. So instead of creating a renamed cgi-bin in every DocumentRoot, I added a single
ScriptAlias /runme/ "/var/www/cgi-bin/"
to httpd.conf and then linked it like this:
<A HREF="/runme/addresses.ext"><IMG SRC="pixel.gif" BORDER=0></A>
I also added a single transparent pixel to the link to keep it invisible but still fool the spiders. Add the runme directory as excluded in the robots.txt and you should be on your way. Muhahahah, and so on.
Money for nothing, pix for free
How about sending a parameter to a page which redirects to the mailto: protocol?
For example:
index.html
<a href="filename.php?x=info">E-Mail Me</a>
filename.php
<?php
Header ("Location: mailto:" + $x + "@mydomain.tld")
?>
There's a spam-blacklist, so how about a spambot-blacklist?
You'd have a standardized spambot trap (like the one described in the article) on various webservers. The new spambot info could go into a "New SpamBots" database (which wouldn't be blocked). Once a day, the webserver would connect up with a central database and submit the new spambot info it's obtained. Then the server would download a mirror of the updated "SpamBots" database which it would use to block spambots.
The centralized SpamBots database would take all of the new SpamBot info every day and analyze them in some manner as to detect abuse of the system (ensuring that only true spambots are entered). E-mails could be fired off to the abuse/postmaster/webmaster for the offending IP address. Finally, the new SpamBot info would be integrated into the regular SpamBot database.
This way you'd be able to quickly limit the effectiveness of the Spambot-traps across many websites.
My sci-fi novel, Ghost Thief, is now available from Amazon.com.
Especially loved "friends"...
Like hotline@mpaa.org, cdreward@riaa.org, senator@hollings.senate.gov for example?
Dear Spambot Authors,
Thanks again for your interest. I hope that we were able to help you write the spambots of the future that will be able to detect and sidestep as many of the above protection schemes as possible. We tried to work all of our knowledge into one convienient thread for your development team to peruse.
Thanks for your interest in SlashDot, home of too much information.
------
Today's Top Deals
Why on Earth would you like to block a spambot? So it doesn't get any more useful addresses? /give/ it a next page. With a nicely formatted word1word2num1num2@word1word2.com, where words and nums are random.
No way, man.
If you realize you're serving to a bot, go on serving. Each time the bot follows the "next page" link, you
Give it thousands, millions of addresses this way.
This would be good to do with known bad addresses, but random addresses only add more unknowing people to the list. You may add 1000 email addresses to the list and slow them down, but if even 10 of those email addresses are real, you've added to the problem. The bad addresses will be taken out as they are found to be bad, and the good ones will be left in. You've signed JoeRandomUser@RandomDomain.com up for all the spam he can handle, even if he has taken great lengths to keep his email address off the spam lists. In theory this sounds like a great idea, until your the guy getting your email address randomly fed to the bots.
"Information wants to be expensive" - Stewart Brand, the same guy who said "Information wants to be free"
I want a mail relay that refuses to process more than 10 mails from any single IP in a 24 hour period. It would be usable for home residential mail, but useless for bulk mail. As an added bennifit it would severly restrict the impact of the latest MS outlook exploit.
The truth shall set you free!
This helps, but not much...
Think about it. With the scarcity of domain names lately, chances are that while the garbage email addresses may not be valid, more than a few domain names would be valid.
So then the spammer fills his database with these non-existant addresses on existing domain names. He then sends his spam to these addresses, and their mail servers not only have to process the message to determine that it's an invalid address, but they also have to bounce the message back as undeliverable.
IMO this is going to use twice the bandwidth, since you now have to consider the bandwidth used by all of those bounces.
You could always use some non-existant domain names for the garbage email addresses, but the spammer could just as easily check a domain name's validity before sending spam to it, making it trivial to remove all of the trash from his database.
Remember, the spammer couldn't care less about sending mail to bad addresses, as long as the good addresses are spammed as well. It's left to the poor sysadmin to clean up the mess.
"A terrorist is someone who has a bomb but doesn't have an air force." -William Blum
Try out the Book of Infinity. It's a CGI that generates an infinite trail of gibberish links. It could easily be modified to add gibberish e-mail addresses to each page.
$5 / month hosted VPS on linux = awesome!
There is another solution: Usually these SpamBots are not able to execute JavaScript...
As described at http://www.joemaller.com/js-mailer.shtml you can combine JavaScript and Images to protect your mail. Made very good expiriences with this one....
But, as stated on the Website: this game is an arms race...
function SeedFakeEmail($Email)> Please don't email $Email</a></font>";
{
echo "\n<font size=\"-5\" style=\"display:none\"><a
href=\"mailto:$Email\"
}
SeedFakeEmail("uce@ftc.gov");
SeedFakeEmail("listme@dsbl.org");
SeedFakeEmail("hotline@mpaa.org");
SeedFakeEmail("cdreward@riaa.org");
SeedFakeEmail("senator@hollings.senate.gov");
Put that in your pageheader and smoke it!
On rahga.com, I use a custom perl script with a html-based form that is programmed only to send messages to me. Here it is.
On stuff like my FAQs, I use igPay Latin Encoded Email: ahgaray atyay ahgaray otday omcay
How about instead, returning pages with the email address abuse@domain-that-spambot-is-coming-from all over them...
.edu, or .gov.
Most spambots know better than to send their crap to email addresses containing things like abuse, root, postmaster,
Also, in regard to the problem of root servers being queried every time a @randomdomain.com is looked up, could you not just use random IP addresses?
I pledge allegiance to the flag...
of the Corporate States of America...
Matter of fact, I think it'd be a good idea to have an open-source email harvester. . . it'd give the good guys an idea of what works and what doesn't, and of course the open-source version would be free, polite to webservers, and best of all would steal thousands of sales from the real bad guys, the fellows who write spambots. (ObPipeDream) With any luck one of them would steal the code and resell it, and the GPL could get a slam-dunk court test.
Shutting down free speech with violence isn't fighting fascism. It IS fascism!
Before announcing new useful project to Slashdot community, create Freshmeat/Sourceforge page first there by eliminating the need for my host to shut me down for execssive bandwidth.
Take a look at these two bits of code from http://www.slickhosting.com/contact.shtml :
O ver="window.status='mailto:hostingsli ckhosting.com';return true;"c khosting.com</A>
<A HREF="mailto:hosting%40slickhosting.com"
onMouse
onMouseOut="window.status='';">hostingsli
<!-- Spam trap
abuse@ (your domain) HREF="mailto:abuse@ (your domain) "
root@ (your domain) HREF="mailto:root@ (your domain) "
postmaster@ (your domain) HREF="mailto:postmaster@ (your domain) "
uce@ftc.gov HREF="mailto:uce@ftc.gov"
-->
$x='S24;r)>63/* h@<5+oZ)32"5cz';$me='phroggy'x$];
$x=~y+ -xz+\0-Tx+;print$_^chop$me for split'',$x;
Make a big macromedia flash site. Let the bot's eat that: this is the thing a lot of company's do.
.doc files.
.doc format.
don't worry, and google wil adapt. They read even pdf and
new thought: make a site written in
Odds are high that this system, should it become sufficiently widespread to be useful, would be vulnerable to poisoning by spammers spoofing spambot traps and causing legitimate IPs (such as Googlebot or large blocks of Net users) to be incorrectly blocked. There are countermeasures against this, but my guess is that the resulting arms race would not result in an adequately-usable system for enough of the time to be worth it. (Remember, the blacklist must update with reasonable frequency for both additions AND expirations, and must have a VERY low rate of false-positives). The authentication of "legitimate" submitters is a serious weakness of such a system. Nice thought, though...
"My strength is as the strength of ten men, for I am wired to the eyeballs on espresso."
postmaster@127.0.0.1 and abuse]@127.0.0.1postmaster@127.0.0.1 and abuse@127.0.0.1
Good idea but, I'm sure spam software has been rejecting 127.0.0.1 for many years.
How about a few people volunteering real FQDNs that all resolve to 127.0.0.1? I realize that people would be volunteering horsepower and bandwidth for DNS lookups, but it would be in the name of dramatically reducing spam. Then, keep a list of all the "loopback FQDN's" and let the rest of us feed those FQDN's into spam-trap generators. Eventually, there would be so many real-looking spam trap email addresses that the spam software wouldn't be able to keep up with the list of loopback FQDN's.
To take it to the next level, you could hide the list of "loopback FQDN's" by making a reverse DNS lookup against a couple of volunteered IP addresses return a random FQDN from the list of loopback FQDN's at the time that the spamtrap page is dynamically generated.
Spammers would never know the entire list of FQDN's that resolve to loopback.
Intelligent Life on Earth
Way too much work. Here's similar Escapade [escapade.org] code:
<QUIET ON>
<html><head><title>Members area</title></head><body>
<p>Hello random visitor. There is a big chance you are a robot collecting mail
addresses and have no place being here.
Therefore you will get some random generated email addresses and some random links
to follow endlessly.</p>
<p>Please be aware that your IP has been logged and will be reported to proper
authorities if required.</p>
<DBOPEN "SpamFood", "localhost", "login", "password">
<FOR I=1 TO 100 STEP 1>
<SQL select * from names order by rand() limit 1>
<LET FN="$Name">
</SQL>
<SQL select * from lasts order by rand() limit 1>
<LET LN="$Last">
</SQL>
<SQL select * from addresses order by rand() limit 1>
<LET AD="$Address">
</SQL>
<a href="mailto:$FN.$LN@$AD">$FN.$LN@$AD</a> <br>
</FOR>
</body>
</html>
-- Ed Carp, N7EKG erc@pobox.com PGP KeyID: 0x0BD32C9B What I'm up to: http://intuitives.mine.nu
I don't stop spambots, I feed them. I feed them phony email addresses and addresses of spammers (gathered from places such as my fake /cgi-bin/formmail.pl). I use
http://www.devin.com/sugarplum/, mentioned before on /. to dish it out!
is that some of the fake emails it generates will be real.
We've recently set up a Spam Troll-box using Vipul's Razor on our new Tux4Kids dev server (you can find our troll box here).
;-)
A troll-box gives Spam-bots a place to send their spam. When this box intercepts the spam, it reports it to the Vipul's Razor network, and everyone else on this network becomes aware of that spam (if they are also using Vipul's Razor to filter, which, chances are they are, it will filter that spam if they get it).
If Vipul's Razor isn't enough, one can even use something like SpamAssassin in conjunction with Vipul's Razor to get even better results.
Of course, this isn't cutting off Spam-bots at their source... but if enough sites were to cut them off at their source, then I'd imagine the Spam-bot authors would get wise to this and devise a way around it. Whereas with something like a SPam Troll-box, the Spam-bots seem to still be working to those running the Spam bots
Well, I didn't trust (1), and (3) just got me a voice mail box instead of a person I could chew out, which I didn't use. That left (2), and I had a wicked idea:
I hit 2, and input the number that I should call if I was interested in the fax (which appeared in BIG text right above the little text). Their own response number should start eventually getting faxes from them or, as I tend to experience, hangups.
Cute story, I know, but what does this have to do with defeating spambots?
I went to the page indicated...
And I scrolled to the bottom, and looked at the source code, and noted two faaaaaascinating things:
First, the HTML on that page is rather clean; I can see no evidence of anti-spambot code on their page.
And second, the "Contact Us" link at the bottom is a mailto:.
By all appearances, their page is vulnerable to their own spambot.
So I had the thought... what if those generated-random-email-address pages were geared to produce not-so-random email addresses? What if the email addresses on those generated-page traps were geared to generate random email addresses at the domains of the various spambot-- (err, I mean) harvester producing companies? Let them see what it's like when less than discerning spammers use their software for evil. Hundreds of Viagra-substitutes! Thousands of hangover cures! Tens of thousands of opportunities to refinance their home mortgage!
This is just an off-the-top-of-my-head idea. Opinions?
You cannot truly appreciate Dilbert until you read it in the original Klingon.
Not if the TLD isn't .com, .net, or .org! There's almost NO chance that it's valid if the TLD is also random.
Remember, the spammer couldn't care less about sending mail to bad addresses, as long as the good addresses are spammed as well.
True, but the their address lists will depreciate in value because the authenticity of most of the addresses would be in doubt.
$5 / month hosted VPS on linux = awesome!
What about requiring all of your users to go through a terms of service page before accessing any parts of your site?
The page could have a form with "Accept TOS" and "Reject TOS" buttons. I wonder how many spambots would submit a form?
And to catch spambots that did submit the form, your TOS could have some clauses that make it a violation for evil spiders (ones that don't honor "robots.txt") to use the site. Maybe you could make||lose a few bucks suing the spambotters who go through the TOS and still harvest your email addresses.
Speaking of spam, I've come across this new program called mailwasher. You can check your mail while it's still on the server, and then - get this - fake a bounced message. There are probably other programs that do this, but this is the first one I've heard of.
Anyway, AFAIK, it's WinBlows only, and available at http://www.mailwasher.com, although right now it seems the site is down, all I get is a 404!
Rather than filling the spider with a whole bunch of (potentially valid) addresses and loading your server with bogus clients you don't want, just make it difficult for them to extract the addresses.
I wrote a bit of PHP a few months ago that applied some spamproofing ala SlashDot (only a bit less agressive) that some might find useful.
Highlighted Source
Raw Source
It performs the following munging, depending on what you specify:
freaky@aagh.net
freaky (at) aagh (dot) net
freaky@aagh.N0SPAM.net.SPAMN0
freaky@aag&# 104;.net
random one of the above
random with entity encoding
all of the above
http://www.xemu.org/mirrors/spambot_trap.html
Ok, just make sure the TLD is longer than say, 5 characters and you can be almost certain that randomly created ones don't exist.
:)
I am fully aware of the non-com/net/org TLDs...just look at *mine*
There are "scanner" traps that start up a session and just drops it (not telling the scanner) which ties it up until the scanner softare times out.
How about writing something for these spambots using a special web server that slowly responds to it's requests (sends out a small packet every 10 seconds) so it won't time out and won't consume much cpu time, and just feeds it a line or two lines of junk with each packet. Have it randomly generate a never ending supply of useless information to keep the spambot happy. While it's busy with the useless site, it's not bothering other people nor is it getting any real addresses.
Who would win this election: Andrew Weiner vs Andrew Weiner's weiner.
..howabout a glue trap?
:-)
1. Publish false mailto: addresses on your web pages in the same colour font as your background
2. Change them to visible, valid addresses by munging them with DHTML properties and a
JavaScript include file (sorry, Lynx users)
3. When a recognizable spam-bot comes in, refuse to load the javascript include file. mod_setenvif and mod_rewrite should help out here.
4. When a probable spam-bot comes in, serve up the page reaalllly slowly, don't close the connection until it goes in CLOSE_WAIT. This ties up sockets on the remote machine and reduces its ability to troll OTHER sites. You can do this by writing a handler for your base directory, checking the browser, and returning DECLINED for friendly people. That should be in, I think the "post read" phase.
5. When a recognized bad address comes through to your mail server (from step 1), slooooow the SMTP transaction down as much as you can (same idea as step 4), and throw an error at the end of the 354 DATA section a few times (to force him to come back!), etc. (Some sendmail internals hacking required here, although it would be much easier to hack if you don't have any real mail and just ran a script from inetd.)
6. Those fake email addresses. Make them all point to a common MX or group of MXes that you control the DNS for. Make sure those MX records aren't used by anything legitimate. Slooooow your in.named down for requests to that domain. A cool side effect, besides tying up sockets on the spammers end, IIRC some OSs can only make one resolver request at a time -- this'll effectively block all of his out outbound spam traffic while he's trying to look up your MX record! Also, make sure the TTL is set to about 10 seconds, just to make sure he comes back the glue trap very often.
How's *that* for spam countermeasures? I wish I had time to write it.
Do daemons dream of electric sleep()?
Memory plus an Apache child. Any solution which causes Apache to be put sleep artificially can and likely will be used as a very effective DoS against your site. Unfortunately.
You don't need to do that.
MX records do that for you.
You can actually have email@mydomain.com when you don't have a box providing an ip for mydomain.com
MX records say "hey, you, all the email for is handled by - as such, you could easily tell your DNS provider to set the MX for any number of hosts to 127.0.0.1
Desperation is a stinky cologne
Or billgates@microsoft.com
Video Game cheats, hints a
The mailto:address@foo.com?Subject=bar syntax was introduced by Netscape 2.0.
Nathan
...so that you can leave them out of your HTML source:
j s
http://artificeeternity.com/includes/linkwrite.
Instructions for use are included in comments. The script fragment that replaces mailto: links in the page will actually shorten your code -- it only requires entering the username and domain once. Also, the @ sign is added in by the script, so the address itself never appears in your HTML.
Ideally you would actually create a spam trap account for this task and use a procmail recipe to briefly explain what you're doing in the forwarded message. That way the raw forwarded headers can't be misinterpreted as your server sending the spam.
I do this very thing and have had great luck with it. I seed multiple addresses on key pages so that uce@ftc.gov is garunteed to receive a number of these pieces of spam. I also send this spam to the newsgroup bot for news.admin.net-abuse.sightings, a newsgroup filled with forwarded spam LARTs for us anti-spammers to search for patterns or previous spamming evidence. You just add "nanas-sub@cybernothing.org" to you recipient list and prepend the forwarded subject line with "(email)". That's it!
Way too much work. Here's similar Escapade [escapade.org] code:
Not similar enough. That makes 300 queries per hit against your database, and I don't think you even used prepared statements. His code slowed their software to a crawl by sleeping. Yours will slow your software to a crawl by excessive database traffic.
Just to make sure it gets said: The email address that's listed here on /. is a spamtrap. Don't use it! My user name in my domain is the same as my user name here. I didn't intend for that address to become a spamtrap, but it was soaking up so much spam it seemed wise to put it to good use.
Warning: This signature may offend some viewers.
Hey... Here's something I found out a few days ago:
http://www.mailutilities.com/aee/
Elcomsoft, who are the makers of the Advanced Ebook processor (remember Skylarov?), also make various email utilities. Although some look like they might have legitimate uses, at least one looks to have *no* legitimate use. (When a tool is designed to scan web pages for email addy's, and DESIGNED to pull out real names&email from web forums...)
Read the above URL and the rest of the site yourself and draw your own conclusion.
- <a HREF="mailto:abc(insert 1000 characters here)@blahblahblah.com">
have any detrimental effect?It's actually http://www.mailwasher.net/.
I'd really like to, but unfortunately, I can't get the script past that lame lameness filter... Yes, I know, I shouldn't have used Perl... If any of the editors are reading this, please consider making that filter less strict. Thanks!
Say no to software patents.
Here is what I do on my website to protect email address
;
Javascript:
function sendmail()
{
var string = 'mail'
string += 'to:'
string += 'webmaster'
string += '@'
string += 'domain'
string += '.com'
open(string)
}
Usage:
<a href="JavaScript:sendmail()">webmaster</a>
This could be expanded to pass the values need to build up the email address.
Chris Beckenbach
Can I claim that all the spam these jerks send me are an attempt at a DoS attack?
The man who trades freedom for security does not deserve nor will he ever receive either. - Benjamin Franklin
OK, so we've got spambot prevention. Now we need some effective form of "Slashbot" protection. I envision a webserver that will detect a high number of referrals from Slashdot and put the server into "low bandwidth" mode, serving pages stripped of formatting and graphics (with links to graphics, of course) in order that content may be delivered in an efficient manner.
Give me my freedom, and I'll take care of my own security, thank you.
I always enter postmaster@warez.slashdot.org in spamforms
But you can do better than that - Give them FQDNs that resolve to Open Relay sites, and use Round-Robin DNS if you can. If you've got your own domain, you can spare plenty of FQDNs, like mail2.mydomain.com.
Depending on how you set up the round-robin, and where the relay machines get their DNS resolution done, you may be able to make them run in a tight little loop around the Korean broadband, or burn expensive international bandwidth between China and Sweden.
Or you could give them random names at various spammer and spamhaus sites, or FQDNs that resolve to the addresses of spammers or spamhausen, or remove-me addresses of other spammers. They may filter out their own, and don't give them obvious addresses like abuse@ or postmaster@, but surely they won't recognize most of them, especially the latest Corrupt Nigerian Official trying to launder embezzled money.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
If you're not messing with DNS, though, there are lots of addresses that can cause trouble:
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
And somewhere out there is a far nastier variant on a teergrube that can keep a typical smtp session up for hours with only a few kilobits/minute, using tricks like setting TCP windows very small, NAKing lots of packets so TCP retransmits them, etc. (It basically works by saying "No, SMTP/TCP/IP isn't a set of protocol drivers in my Linux kernel, it's a definition of a set of messages and there's no reason I should user a bunch of well-tuned efficient reliable kernel routines when I can send raw IP packets myself designed for maximal ugliness."
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Golly gee, let's see here. Ways to thwart the spambots.
You can URL-encode and un-mailto your address.
But spambots can still read most plaintext email addresses from the text itself...
Then encode your email address into a piece of javascript.
But many normal users don't have javascript turned on...
Then write your email address into a GIF or PNG.
But certain types of disabled people and lynx users won't be able to view those images...
This author would argue that those two are one in the same. But still, you can also obfuscate your address for the user to figure out, providing directions on how to unobfuscate it. (NOSPAM.bob@NOSPAM.hoser.com)
But there are many users who are too dumb to unobfusicate the address...
Then write a web page with a form for sending the message... the email address remains hidden.
But this is insecure / stupid / not fully supported by Mosaic 0.13beta...
Then whoever can't use one of the above methods can go sod off. I plan to use most of these, grouped together into one contact.html page on my personal web site. If there are a couple of users in the world out of thousands who can't contact me due to technical or mental limitations, then dang them to heck for all I care.
You see, it's a balancing act of preferences. Would you prefer to let (literally) a couple users slip through the cracks, or would you rather get bombed by potentially hundreds of spambots? Your choice...