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Why Blacklisting Spammers Is A Bad Idea
Roland Piquepaille writes "For the last two months, an eternity in Internet time, I was unable to reach -- and to contribute to -- Smart Mobs, the collective blogging effort around the next social revolution initiated by Howard Rheingold. Why that? Because an unknown customer of Verio decided it was a spamming site and asked the company to blacklist the site. Verio complied -- probably without even checking it -- and my problems started. It took me dozens of e-mails and phone calls and two visits to the headquarters of my french ISP, Noos, to fix the situation. More about this horror story is available here."
And other RBLs require usually multiple reports from multiple sources. And you have fairly straightforward way of getting de-listed, too.
What's with the current boo-hoo over blacklists? Do we have some kind of spammer astroturf going here?
Break into the lobby of the ISP, guns in hand, and force them to remove the site from the blacklist. It's what I do when I'm pissed.
And why did you staple the trout to the RAM?
This article should have been called...
"Why it's important to have good policies and procedures in place when blacklisting spammers"
I use blacklists to mark probable spam, but still generally see it. Recently, some people had reported an email from GoDaddy (domain registrar) that was only sent to customers, and it was asking them to very information. If, say, my ISP was blocking email from them based on this, I'd never see it. ISP's should err on the side of caution, let users take more risks if they personally desire.
"blacklisting" in this article refers to completely block an ip address. This is not a "bad idea", but complete nonsense. First time I've heard of something like that. This is not to be mistaken for using an open relay blacklist or similar, which only blocks mail from a certain address. I bet those "network administrators" clicked on some fancy "block site" button, not knowing what they were doing...
RTFA. Verio was doing blacklisting on ALL PROTOCOLS for this ISP. The guy could not even GET TO THE SITE.
Verio blocking HTTP access to other people's spam pages? I have I wandered into another universe again?
One line blog. I hear that they're called Twitters now.
The fact that a strategy (such as blacklisting) can be mismanaged and that it is not invulnerable to abuse does not necessarily make it a "Bad Idea". It just means it needs to be managed more carefully, and better secured from abuse.
Why is the blacklist being done on a domain level. Spam is usually email....so block the email address. That is simple enough to do with intrusion detection systems, some application level firewalls, and if your really bored....an access list on a router. Whoever decided to block ftp or http to stop spam was not all there. They should have stopped smtp traffic from there instead and been done with it.
Black listing of spammers is a good idea, we just have to make sure we are only blocking them and not innocent bystandards.
Stop signs are only Suggestions
Use some common sense editors when presented with a story that seems unusually slanted please take it at face value. This is why corporations such as verio need to be made aware of their policies not working not that black lists do not. Blacklists are the only thing that works against spammers and they know it. So how do they fight back by using the blacklists against regular sites to try and disrupt users service so that people might think twice about using them.
Instead this article should be title "Why Blacklist Do Work" and what spammers are doing to try and disrupt them.
Quoting from the article:
Maybe it is a good time to change ISP?
Where was this in the FA? I'm interested in the technical details, but I can't seem to find any.
Your credit card information wants to be free.
From the article: My ISP has a partnership with Verio to handle its traffic in the U.S. When Verio blacklisted Smart Mobs, any request from Noos went unanswered -- sorry, there was the (in)famous 404 error.
I want to be sure I understand this correctly. Verio wasn't (only) discarding mail from Smart Mobs, because they thought it was spamming site, they were refusing to pass through http (or other) connections to it?
Discarding mail is one thing, but blocking an IP address is quite another. What's the justification for this? To prevent the (supossed) spammer from profitting from the spam, by preventing anyone from connecting to it to (presumably) buy the product touted in the spam?
Discarding mail from a spammer can be justified, by, among other things, the argument that spam mass-mailings strain system resources. But connecting to sites happens all the time -- an ISP should should be set up to handle that traffic, and can traffic to sites touted in spam really increase the volume that much?
To me, this seems like a dubious policy on Verio's part -- even without the problem of mis-identifying sites as in the case of Smart Mobs.
Opinions on the Twiddler2 hand-held keyboard?
I left an HTTP proxy on on an open port - on the same machine that does SMTP. I didn't even know that spammers could relay via an http proxy using a PUT to the local SMTP server. mea culpa.
I fixed it in 3 days (too long, I know).
I contacted mail-abuse.org and submitted a removal request. It took them 2 weeks to take me off the list.
It frustrates me that their site is so unresponsive to removal requests, and that they fail much of their process. They were supposed to send email at several stages, which they did not do. The email they did send was badly formatted (broken urls, urs that weren't relevent).
I won't ever use an RBL because they just don't seem responsible.
Yeah, I know - pot kettle black. But I'm not supplying a service to thousands of users.
Someone anonymously submitted our MS Exchange server (I don't blame em *grin*) as a spam relay, despite the fact that it is not. As said in the original post, they didn't even check the server they just blacklisted it.
:(
The first thing we know about it is when members of staff come to us and complain that they are getting error messages such as 'denied' when trying to email important people.
Sigh.. in fact I have that very same problem waiting to be tackled when I get back on Monday morning. And its always such a ballache to get your mail servers removed from these block lists...
"Hey! Unless this is a nude love-in, get the hell off my property!!"
First of all, the idea of Verio blocking spammers is laughable. They have always been a haven for spammers and everyone here probably already knows that.
The real issue, however, seems to be this guys ISP. I mean honestly, what the hell is wrong with them? If I had called Speakeasy with this sort of problem, it would have been taken care of that day.
-sirket
The tite should read: "One of the many problems with spam blacklists" -Jaxn
http://radio.weblogs.com/0105910/categories/sideba rs/2003/11/09.html
Read that.
I have an earthlink.net account and a couple of weeks ago I was issued an IP address in the dreaded slashdot BANNED! file. Pity poor me, getting the big orange screen telling me about the terms of use and how, as a BANNED! IP addy, I was unable to even read them. Fortunately, the evil orange BANNED! page quoted me a few of the offenses that might have gotten 'my' IP banned. I must have spammed the input queue or posted a PWP (page widening post) or somesuch.
/. never forgets.
/. -- can you imagine the suffering that such a fate would cause *you*??!
Of course, it wasn't me. It was some other Earthlink customer who, sometime in the past, was issued that same dynamic IP address and committed the unpardonable offense. That customer has moved on to a new IP, but
It was hell. I spent *hours* unable to access
Eventually, I was issued a new IP address from earthlink and was back online as the ageless Sun Tzu once more. But I still live in fear that someday, perhaps when I least expect it, the evil orange BANNED! page will return to haunt me. This is the personal hell that I inhabit and it is here that I shall remain, until I get a clean static IP address of my very own. I live for that day.
--
Send us your Linux System Administration articles
Geeky modern art T-shirts
The last time I checked, being a user of an ISP or the company that carries the packets means you're a customer of that ISP/provider ... your money is used to pay for their services.
i am a soviet space shuttle
So the question presented by this article would be "WHY is blacklisting spammers a bad idea?" Unfortunately, it doesn't answer the question.
The blurb mentioned by the article submitter is the entire coverage of any such activity. The rest of the piece then goes on to complain about the user's ISP. Those who haven't RTFA'd can feel comfortable in skipping this one.
I'm sure this submission will provide nice fodder for expressing annoyance over spamming and horror stories of "collateral damage". But then - we've had plenty of those before. It would have been nice if an article had provided some framework around this kind of conversation.
This article doesn't.
The good it does is far outweighed by the bad. Just like everything else in life, mistakes will be made. You can have a problem with the process to correct mistakes, but advocating RDNS blacklisting should go away doesn't make sense.
I love hearing these "horror stories" about people listed by some well-known DNSbl like SpamCop or SPEWS, telling us how unfair it was and how impossible it was to work with the list maintainers, but they never provide any details so we can't investigate their case.
Of course, in one case a company did provide extensive details that, when looked into, showed that their listing was perfectly justified.
STOP MISUSING APOSTROPHES, YOU MORONS!!!
The thing we all forget is that spammers are human. If a single address is being blocked, then they change the addresss. If they are spoofing, there's a chance you can incorrectly block a whole domain because of one idiot who setup an open relay. Case in point, at work, all e-mail on the .biz top-level domain is blocked because of the amount of spam taht is recieved from it. What if someone we'd like to do bisness with is on that domain? Alot of the typical comapnies you do musiness with have the .com tied up but if your starting a new business, sometimes the only one available might be the .biz. I personally have given up and try to filter as much as I can knowing that even that won't help.
Gorkman
How about making use of micropayments so that sender's account is charged some nominal amount that goes into receiver's account?
How about not? Of all of the proposed solutions to the spam problem, micropayments are the worst.
Yep, I am tired of getting the dreaded pink slashdot screen (DPSS), after hitting several times F5 it loads the page correctly (weirdly developers.slashdot.org is the hardest to bypass) /. bans spain? /. ban on spain lame /., one of the addresses listed in the DPSS, but to no avail , the /. admin want me to contact my adsl proxy administrator and from there the Telefonica "techies" (another joke) and /. admin resolve the matter, what a JOKE any one in Spain will LOL at that thought, its impossible to talk to any one in Telefonica, they have a monopoly and frankly they dont care about each users because they know we CANT switch) /. is very kind to ban ,thx very much. (and no its impossible to change that, i cant switch adsl provider because all of them are resellers of the main one, and since the main one uses a "transparent" proxy .....
Why
Yep I know my evil "isp" hijacked the internet and put a transparent firewall but I CANT switch "isp" there is only one "real" adsl provider in spain Telefonica, the other ones are resellers of the same product.
(I tried once emailing
Note: All adsl in spain goes to port 80 using only a handful of IP adresses which
To get kicked from Verio, you have to burn down a network center or something like this. About 500 mails from users to abuse@verio.net for one spamvertized website netmails.com and no action taken ==> They do nothing against spam. They tolerate spam.
.
Check for yourself: Verio's Listing
I use blackholes.us to block (port 25) entire countries (cn, kr, tw) and ISPs (Verio, interbusiness.it...) that do not qualify (in my standards) for connecting to my mailserver.
NSG
Grundgesetz * 23. Mai 1949 - 30. November 2007 - http://www.vorratsdatenspeicherung.de/
I dare you to try and contact the Earthlink Network Abuse department. At my work, we are a (legal) online betting site and were getting pounded by several Earthlink IPs grabbing our free odds.
With megs of apache logs for each IP address, Earthlink network abuse must have taken the week off. 17 Emails and 8 calls. With NO answer, NO response on anything.
We cannot just block all of Earthlink's dynamic numbers because of ten insipid users. I wish death on all the sysadmins at Earthlink and I curse their children with webbed genitailia.
((Before replying with suggestions to do on my end, they have been tried. mod_throttle wasn't an option, dynamic temp bans had to be watched, blah, blah, blah.))
When modding "Informative", please make sure it both has a source and IS actually informative.
Based on this story, it seems Verio decided to block the presumed source of spam by means of the routers. That's a rather extreme measure. Doing such things in routers, whether by access list, or by blackhole routing table entry, is not nearly as easy, and does not scale as well, as blocking at the receiving mail server. But they may have wanted to do so because so many mail servers are run by clueless people that can't configure their way out of a paper bag.
I block spam source at mail servers, not routers (except in very extreme cases, but there are current none blocked at routers). That gives me the option to whitelist specific senders and/or specific recipients. So I'd say the real issue he is not that blocking/blacklisting spammers is bad, but that blocking them in stupid ways that lose control is what is bad.
Blocking spam and spam sources should be an end-point decision. There are risks in blocking, and different people have different needs and different sensitivities to that risk. Even your own ISP shouldn't block spam for you unless you agree to it with the understanding of how they are doing it. The best solution is for you to have total control if you wish, particularly in the ability to whitelist, and even blacklist, specific exceptions you want. Those who don't know the details of how this is done would have to delegate that to someone (such as their ISP).
Even content based spam filtering can be broken. What if my girlfriend sends me mail telling me what she's going to do with certain parts when she comes over tonight. I sure would not want that to bounce. Of course I can whitelist her email address (and hope her computer doesn't get infected by some spamming virus).
Blacklisting spammers is good ... when done right. Verio didn't do it right.
now we need to go OSS in diesel cars
There are only a couple of possibilities here. One, you are running your own server on a consumer account with a dynamic IP address, in which case you are likely in violation of your AUP, or two, your ISP is utterly clueless and has put their static IPs in the middle of their dymanic range.
Either way, get a real provider, and your problems will disappear.
"Why Blacklisting Spammers is a Bad Idea: It Takes Up Valuable Time that Could Be Spent Tracking Them Down and Killing Them"
Verio doesn't blacklist spammers. Verio HOSTS spammers. Verio is friends with spammers. Verio has a long and storied history of supporting spammers, so I think it's far more likely that Verio got blacklisted and not the other way around. This guy should have switched ISPs but he completely misunderstood what happened here - he thinks that Verio is blocking him from viewing some random web site. What actually happened is Smart Mobs' ISP blacklisted Verio, probably with good reason.
First, it's obviously a bad idea to block all IP traffic for an entire netblock (except under extreme circumstances -- attacks, for instance).
Spam is a huge problem, and there are some very effective DNSBL's (DNS blocklists) out there that can let a mailserver reject mail coming from a certain IP address. There are many different DNSBL's out there, and each has their own policies on what IPs they will list, how they will de-list, etc.
I don't like DNSBL's that list IPs based on non-spam related criteria. Examples include: country/continent of origin and service class (consumer vs. commercial). Blocks based on such criteria just divide the Internet, and don't even take into account where spam is coming from. I think it's a slap in the face of the Internet for a company to say, "I'm going to block all traffic from dynamic IPs, because they are not commercial connections".
Then there are the blocklists that block IPs that send spam. I like this approach because the lists are designed to block what I don't want; spam. sbl.spamhaus.org blocks regions of the Internet that perpetually send spam. blackholes.easynet.nl similarly list established spam sources. relays.ordb.org and list.dsbl.org block open relays and proxies that were found to be points of abuse.
So some bandwidth provider accidentally stuck a site on a blacklist. And then it got fixed. Is there some important angle I'm missing here?
Don't tell me, because of this upset you missed meeting up with four thousand other bored office workers in a public place to do something 'wacky'? Boo freaking hoo.
Preferences > Homepage > Customize stories on homepage > Authors > Zonk > Uncheck
Over the past 6 months, some 65% of spam (and spam attempts) that my ISP received came from less than 0.16% of the assigned IPv4 address space.
Almost 2/3's of the spam we saw was sent over SMTP connections from one of 77 CIDR blocks (ranging from /16 to /30 in size).
These 77 CIDR blocks represent less than 1/6 of
1 percent of the assigned IPv4 address space.
BTW: The CIDR list growth factor is not much when you move from the 65% level to the 90% level.
Spam is truly a world wide problem. Those 77 blocks, by national/region, break down as follows:
"Yes, Virginia", a few IP address blocks do transmit most of the spam.
chongo (was here)
...that you're perfect, and have never done anything ill-informed, spiteful, purely accidental, or just plain stupid. Therefore, you can tell people not to fuck up in the first place, because clearly the rest of us just aren't trying hard enough.
The rest of us, sadly, aren't interested in trying hard enough, especially if it results in as much difficulty as you seem to have in extracting your cranium from the depths of your large intestine.
That said, I do agree that two weeks isn't an irrational amount of time for this. If it had been two months, though, I would say that they were, in fact, being irresponsible, because they said they were doing something, and then they didn't actually do it, and in fact damaged someone's personal life and potentially their business for making one simple, easy-to-make mistake.
At some point, if you volunteer to undertake a project, and then in the course of doing so you dick someone over in an easily-prevented manner, you are acting unethically. Doesn't matter that you volunteered: if your actions can screw up someone else's life, you have the obligation to be careful of them.
I try to avoid killing pets in the road, if I can do so safely. It's certainly not illegal to run over a cat, but it's certainly not nice. The argument that 'they shouldn't have let fluffy escape out the window that their nine-year-old accidentally left open' does not, somehow, cause me to decide not to (gently) step on the brake.
I know, I know, I'm the anti-libertarian, right? Saying that we actually have some sort of obligations not to actively screw over our fellow man? God, I'm a pinko commie symp! Shoot me now! Or something.
Sheesh.
-fred
Sign #11 of Slashdot overdose: You see the phrase 'moderate Republican' and you wonder if that would be a +1 or a -1.
What's needed is a two pronged approach. One prong is legal and is being followed fairly well; pass laws that make spamming illegal. The other prong, which is still under development, is to make technical changes to email so that spammers can't hide their addresses.
First, I don't share your glee about current laws and the direction they are taking. I fear email will end up like broadcast radio and TV - only people who pay big bucks to the government will be alowed to run a mail server. The result will be as dismal as broadcast media is, but worse because mail is personal. Imagine licensed spam and every email service being like Hotmail - a spam in every can! Your email will always be searchable by government agencies and spammers if people like AOL and Microsoft have their way.
How do they get there from here? They are already half way there. Blacklists are a part of it. Any ISP that does not prevent their users from running mail servers gats on M$ and AOL blacklists, regardless of the actual volume of spam. Convienetly enough for them, this puts further pressure on smaller ISPs and eliminates competition, compliance or no. Another way to get there is by creating mechanisms "so that smappmers can't hide their addresses". This would create the kind of central authority that the internet was designed to avoid. Wanna bet who will run that central authority? The smarter you make the net, the dumber and less free it becomes.
Laws making spam illegal, with reasonable definitions of spam are the only way to kill spam. The IP address of the spammer should leave a large enough trail for people who really want to bust spammers to follow, so it is indeed practical. Some recent turns are good, I just hope it applies to the big boys the same way it applies to the smaller ones. Somehow I doubt it, despite small charges against ATT. No spam is ever acceptable on a medium that was designed to work on pull and our laws should reflect it. If France can keep people from selling Nazi junk, the USA can halt spam if it wants to.
Friends don't help friends install M$ junk.
Better a million spammers go free, annoying billions of people, rather than temporarily inconvenience a handful of innocent domains? I'll take that inconvenience as acceptable risk for living in a world populated by asshats.
Mr. Spock had it right.
Leaving a proxy open for raping by spammers doesn't make you a bloodsucking demon, but it is definitely grounds for having your IPs locally blocklisted.
It frustrates me that the http proxy:
1. Didn't warn me that this was an issue upon install
2. **Allowed this to happen at all**
I have submitted a bug to the developers. This is a known issue, though I'd never heard of it before, nor had 2/3rds of my geek (professional programmers, recreational sysadmins - which describes myself as well) friends. If http proxies blocked all requests (or at least PUTs) to localhost/127.0.0.1 and all know network interfaces on the local machine, this kind of thing either wouldn't be a problem, or would be much less a problem.
Again, pot - kettle - black. Still, good software wouldn't allow this kind of thing in the first place, and recreational sysadmins wouldn't have to worry so much.
Finally, as I'll mention in another thread, I only discovered I was an open relay when my DSL line acted up (total "lucky" coincidence) and I did a lot of investigation on the server. I discovered a huge email queue (which I nuked) and lots of RBL delivery rejections in the mail log. If they had sent ONE message to root@[my ip address] I'd have found out immediately and shut it down within a day.
your ISP has explicitly signed up to SPEWS because it works. it works because it encourages ISPs to be RFC compliant. it's for the greater good: i don't *care* if it breaks your email to your mom on a blacklisted ISP: it's your ISP's business decision to ignore spam complaints and become spam-friendly. natural selection says their customers get pissed off (step one: looks like it's working so far) and then jump ship to an ethical ISP. eventually the spamhauses go bust.
You're good with the SPEWS line, there, but there's good reasons why any admin with a clue doesn't use that fucked up list.
(1) SPEWS is ineffective. It might have some effect if your goal is to drive spammers away from a given ISP, or drive customers in general away from a given ISP. But it won't significantly reduce the amount of spam you get compared to using the lists with a philosophy that involves far less collateral damage. But by using SPEWS, you WILL block hundreds or thousands of times more legitimate emails. If you (the list USER) wish to use the inconvenience of your customer base as a means to punish an ISP with spamming customers, then by all means, use SPEWS. However, if you think your first duty is to maximize spam droppage while minimizing false positives, SPEWS is NOT for you.
(2) SPEWS is inaccurate because of how it is organized. For example, one ISP I used had a spammer, and a clueless staff. After the SPEWS listing hit us, we worked with them to clear out their spammers. They did so; but one set up across town with their own space, and had a very similar name to the ISP. SPEWS decided the ISP was "hiding" its spamming on another block, and listed all blocks (the ISP and their former customer) together, despite different names and addresses on their ARIN registrations. To this day, the ISP remains in SPEWS because the other company spams. Of course, since Collateral Damage is SPEWS middle name, this is of no concern.
(3) Run by fanatics. Much like the 'Eat Your Spews' crowd; they're just the shame of all of us who'd like to see spam stop and would like to take reasonable countermeasures. I get over 1000 spams per day to my 8-year-old email address (most of which are oblitterated by spamassassin), and I wouldn't think of using SPEWS.
(4) SPEWS damages the innocent and does so without warning. Even if you're incredibly conscientious about NOT spamming, you may one day discover a horde of bounces because you are on SPEWS. Now without warning or cause, you will now suffer significant economic damages even if you do immediately exactly what SPEWS would like you to do: switch ISPs.
(5) Because of the sudden effect of (4), you probably will not; you will probably begin immediately routing your mail through a third party, thus rendering SPEWs useless, and simply costing you more money, slowing delivery, wasting bandwidth, etc.
(6) Because SPEWS must, by necessity, delist organizations who stop sending spam, the whole process only serves to make spammers be clandestine and move from ISP to ISP. And so they do; they still show up in ALL the same places. They just move on more often. And the problem is never solved. I'm sure you've noticed that there's still no shortage of spam and years of SPEWS listing places hasn't even dented the problem. But it has cost billions of dollars of productivity and other collateral damage trying to deal with the effects of SPEWS.
Basically, SPEWS is the terrorist anti-spam organization. It is threatening to blow up mail delivery if the spammers don't capitulate. Whether SPEWS works or not is really irrelevant; spammers will always move on and find new ISPs, and at best, SPEWS makes them move more often. Meanwhile, the innocent suffer, because the cure is worse than the disease.
Now, one thing I do agree with: you have every right to use SPEWS. But realize that most of your users would never concur with what you're doing, and they only accept it because they are clueless. Almost every ACCOUNTABLE organization (typically, corporations) that tries to use SPEWS stops immediately, because it is UNACCEPTABLE to have a 100:1 ratio of false positives:true positives. The shame is moronic ISPs like pacbell.net signing their servers onto SPEWS and fucking their ignorant customers out of a ton of their legitimate email.
So, it is perfectly accurate to call SPEWS the nuclear bomb of blacklists. It can and does do enormous collateral damage, most of the IPs it blocks are used by responsible or at least innocent net