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."

Comments

ORBS

[olman]

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?

Re:ORBS

[PurpleFloyd]

The current "boo-hoo" over blacklists can be mostly summed up by one word: SPEWS.

They operate on the "nuclear bomb" method: list spammers, plus anyone using a "spam-friendly" mailserver (a definition that can be stretched to cover almost anyone) or anyone who is simply "suspicious." Oh, and you might also be listed if your new IP block was once used by a spammer. Don't worry, though. You can just wait a few weeks and lose massive amounts of buisiness because many customers can't recieve email from you and have no idea why - they just think you aren't responding. Or you can go onto NANAE and post a delist request, which will get you nothing but "Whiner! Eat your SPEWS, it's good for you!"

To be sure, a large portion of the problem comes from ISPs implementing SPEWS incorrectly - silently dropping all IPs listed, not just tagging level 2 and dropping only level 1 (confirmed spammers), and the spammers have created this problem themselves. However, SPEWS' "list 'em all, let God sort 'em out" approach is irresponsible, particularly when they know that ISPs are applying the filtering with a wide brush.

Re:ORBS

[Eggplant62]

[SPEWS] operate[s] on the "nuclear bomb" method: list spammers, plus anyone using a "spam-friendly" mailserver (a definition that can be stretched to cover almost anyone) or anyone who is simply suspicious." Oh, and you might also be listed if your new IP block was once used by a spammer. Don't worry, though. You can just wait a few weeks and lose massive amounts of buisiness because many customers can't recieve email from you and have no idea why - they just think you aren't responding. Or you can go onto NANAE and post a delist request, which will get you nothing but "Whiner! Eat your SPEWS, it's good for you!"

Incorrect characterization of SPEWS methods. From my own personal observations, a SPEWS listing starts out with the spammer's IP addresses based on spam received at multiple spamtrap accounts. Complaints are filed by the people who run the SPEWS list and, of course, they do not identify themselves as SPEWS operators in those complaints. Some time elapses (I'm not SPEWS, how should I know how much time exactly?). Either the spammer is removed (Yay! The listing drops off the list) or the complaints go ignored and more spam is received at the spamtrap accounts. The listing gets widened to the /24 in which the spammer space is included (this may happen immediately in the case of a spammer identified by Steve Linford's ROKSO (Registry of Known Spam Organizations) at spamhaus.org (may be difficult to reach due to the Slashdot effect or DDoS by virus)).

Lather, rinse, repeat the above until someone at the responsible ISP who received the original complaints wakes the fuck up and notices the situation, usually after their own customers are screaming at them, asking them to fix the problem that got them blocklisted. Then again, this is all laid out in the SPEWS faq in fairly clear, easy to understand language.

If ISP's are dropping mail from both level1 and level2 listings, they've made their own bed and are now laying in it. Only an idiot would block on level2 listings as they are meant as an historical indicator of problems with an ISP and do age off after an indeterminate period of time, again outside my control or knowledge.

SPEWS is the only thing thus far in the war against spam that actually has an effect at the ISP level to get some of these outfits to wake the fuck up and see what's happening in their own abuse@ mail accounts. ISP's think they can continue to shine on the spam problem, thinking they have no responsibility for their customers' actions. We, the users of SPEWS blocklist, say otherwise.

If I decide I don't want mail from a corner of the Internet that has sent me nothing but spam, that's my right. If I decide to rely upon the opinion of another Internet service who tracks this kind of information for themselves and elects to share it with the public, that's my right also. SPEWS works for me and mine.

Why Blacklisting Spammers Is A Bad Idea

[wo1verin3]

This article should have been called...

"Why it's important to have good policies and procedures in place when blacklisting spammers"

Re:Why Blacklisting Spammers Is A Bad Idea

[sweetooth]

No kidding. The primary problem is the ISPs and thier upstream.

Re:Why Blacklisting Spammers Is A Bad Idea

[rgmoore]

Yeah, because blacklisting has been so effective thus far, we just need to do more of it. Yeah, right. Blacklisting is basically playing a game of whack-a-mole; it makes things a bit less convenient for spammers, but doesn't seem to be doing them serious harm. OTOH, crippling the email of innocent bystanders who happen to share IP blocks with spammers seems a rather steep price to pay for something that does very little to stop spam.

Spam is a tough problem, and it's going to take more than just vigilante action to deal with it. 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. Neither one will succeed alone- laws can't help as long as spammers can hide, and making spammers stand still won't help if there's no legal recourse against them- but the combination of the two should help a lot.

Just to clarify

[Nachtwind]

"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...

Non sequitur

[ScottSpeaks!]

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.

Improperly done blacklist

[DaEMoN128]

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.

Re:Improperly done blacklist

[spicedhamhawg]

Speaking as someone who fights spam for a living, effective blocking requires a combination of techniques. You need to filter on sender (both envelope and From:), sender domain, sender IP, and content filters.

Your statement that whoever decided to block ftp or http was not all there completely misses the point, I think. If a site is known to spamvertise, blocking *all* traffic to/from that site is actually a pretty good idea. Why? Consider why spammers send spam: to generate traffic to a web site, an email address, a phone number, some way to contact that. Since they know any email address they use to spam probably won't last as long as fart in a room full of air purifiers, the contact link is usually URL, whether by domain name or IP address. If they spam and you put in a filter for that spam, they may never get that spam through again, but they may still get some buyers from among your (stupider) customers. However, if your policy is to block all traffic to/from that IP address, they get zero traffic and zero business from your netblock and you really hit them in the wallet.

Verio's idea is good, but someone dropped the ball on implemenation in this case by not checking the facts before blocking.

What I'd like to know, though, is why the author of the article uses an ISP as bad as Noos. They sound so bad they make even wanadoo.fr (gee, speaking of spam!) sound good in comparison. Someone at Verio apparently made a mistake, but if so many people at Noos weren't so incompetent (did the PHB character come from their, I wonder?) the situation probably could have been resolved in a day or two.

Am I understanding this correctly?

[orthogonal]

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.

Answering the question.

[_Sprocket_]

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.

Wrong. Not perfect != "bad."

[the_dreadnought]

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.