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The Measured Effectiveness of Blocking Asian Spam
fadden writes: "I recently started blocking IP addresses in China and Korea that were sending me spam. Instead of a blanket ban, I only blocked the subnets from which spam was being sent. After my first week of scanning and banning, I wrote up
a report on the effectiveness of the blocks." In related news, SSKennel adds that: "The U.S. Federal Trade Commission has discovered (prepare to be amazed!) that revealing your email address in chat rooms can get you spammed. It claims to have taken action against spammers who harvest email addresses and use them to send fraudulent spam." Shocker!
We've had to block a number of Korean & China-based IP's in recent months (especially during the Summer). In addition to blocking a number of temporary (PPPOE and such) IP's by domestic service providers, (read: Comcast), the foreign IP's seem to be more static, but also offer a higher quantity of spam. (Are a number of these just open relays?) Though, in our case, it's usually short-lived. Except for Klez, which is the devil.
Good point about the pig singing. While Comcast is extremely unhelpful (bordering on incompetent), foreign ISP's don't face any accountability. There's no decent legal recourse. So blocking the IP is the simplest route.
Has anyone else seen a significant amount of spam from Brazil? Where is the onslaught of OSS Bayesian filters?
Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety
"The U.S. Federal Trade Commission has discovered (prepare to be amazed!) that revealing your email address in chat rooms can get you spammed. It claims to have taken action against spammers who harvest email addresses and use them to send fraudulent spam." Shocker! "
Revealing your email address on Slashdot can get you spammed. You may have noticed my sig says "Sig: I'm performing an experiment on the origination of SPAM, don't email me.". What I did was I set up a junkmail box and pointed my Slashdot email address at it. The only place this address has ever been made available is in my user address that is displayed whenever I comment. When this address is e-mailed, it automatically responds with "thanks for the unsolicited mail!" I don't read the messages unless somebody responds to it.
What prompted me to do this was the 'armor plate your email address' feature in my user settings here on Slashdot. It made me curious if having my e-mail address viewable in the comments I make would mean I'd recieve lots of Spam. My curiosity is satisfied: You can get a good deal of SPAM if you don't use the 'armor plating'.
You know what? They don't just look for e-mail addresses to send mail to. They also use the e-mail addresses as reply-to addresses. I found this out when I got an email from a guy who was puzzled by my auto-responder emailing him. It turns out that somebody sent a message to me and used his address as a reply-to address. Weird, Iddn't it? Fortunately he was very nice and we got that all settled, but it is a little disconcerting that the addresses are used in ways like that.
When I first started this experiment, I responded to the messages I got. I accused one guy of harvesting my address without really reading what the message said. Turns out, the guy ran a mailing list for local (to him) volunteer firefighters announcing a meeting. This wasn't the type of event that somebody would 'direct market'. Heh. Evidentally, somebody volunteered my user address only displayed on Slashdot to his list. How weird is that?
I am extremely curious if anybody has any insight into the motivations of people who'd use email addresses in these ways. I can understand somebody using my email addie as a reply to address, but I have no explanation for why somebody'd volunteer me for a volunteer firefighter's list.
I've invested significant money some years back in a domain name so that I could give my clients and friends an easy to remember, unique email address. I consider it a significant investment, because it looks good on a CV, business card, or letterhead, is easy to remember, and it cost me time and money to establish it.
However, a number of spam companies have picked up on my email addresses at that domain, and have distributed it on a number of those unpteen-million address CDs sold to other spammers. I recieve over 100 unsolicited emails a day. Now, I try to filter them with software filters, but due to the hit-and-miss nature of heuristic filters, legitimate mail is deleted on occasion.
The way I see it, my unique and expensive email address has been devalued by these spam companies, because the whole point of buying that domain name was so that I could use it publically. If I have to keep it a secret to avoid spammers, it is worthless! I can't even use it as an example while writing this article, because it would be picked up by yet more spammers.
I wonder why nobody has tried suing along these grounds. Think about it: If some company had invested time, money, and effort into setting up a toll-free hotline for their customers and/or clients, but had the service ruined by telemarketers jamming the system with 100x more junk calls than the real calls the company recieves, the next outgoing call would be to a lawyer!
Using Hotmail alone doesn't get you spammed. I've had a hotmail account for over a year now and haven't received more than 20 pieces of "unrequested" spam in total. I'm moderately careful with my email address, but it does get out there every so often. Also my email adress isn't terribly hard to guess (matt_allen_g....), and I don't have the Hotmail spam filter turned on. Maybe I'm lucky, but my experience does disprove the hypothesis that ALL hotmail accounts get spammed, simply due to the fact that they are hotmail accounts.
The /. crowd always seems to be talking about how huge the Asian spam problem is. So as an experiment, I've been keeping my spam in a separate folder for a few months, and less than 3% of it is Asian in origin (counted by relay server used AND the spammer itself). Over 70% of it, originates in the USA, and are mostly USA cons/scams/pseudo-products etc (diplomas, anti-spam software, spam software, porn sites, "hot strock investment advice newsletters", "work at home", MLM etc, "lose weight", search engine 'promote your website' offers etc).
Why the discrepancy, am I just an outlier, or are slashdotters exaggerating the non-US-originating spam problem in relation to the US-originating spam problem?
You should have seen what happened when I put a throw-away email address in my away message on irc. Suddenly I was getting 1000 messages a day...scary
I live, work and travel in Asia. I speak Japanese, Korean and Chinese (I'm a native English speaker, from Calif). I don't send mail...I talk to them in person. My situation is unique, I agree. And it's not viable for everyone that may consider helping.
:)
I'm trying for a pragmatic approach, and I would never suggest that simply sending an email or making a phone call would be helpful. The admins I talk to want to fix things, but until a focused effort is made to help them (docs in their languages, etc.), things won't change, I agree. Certainly complaining isn't going to help...and ignoring it isn't going to make it go away.
I'm working on it the best I can...one admin at a time
Since a few people are posting about anti-spam methods, I thought I'd go over my idea to counter spam. Currently I am not actually using this procedure, I have just been pondering it for awhile.
/dev/null. Ahh, a life of no spam!
First off, the core of this system relies on whitelist-confirmation. This means that first time senders are given an auto-response email which must be "confirmed" in order for their message to deliver. Once they have done this, they are whitelisted, and all email from them passes through. TMDA is what I use for this job. I leave my email address "unarmored", because no spam can get through. When I check my mail in KMail, there is no spam.
However, all is not perfect. After many many months of using TMDA, I still find myself sifting through the "pending" folder on my mail server, which keeps hold of all the mails from unconfirmed senders. I generally do this every couple of weeks, and there are often at least one or two legitimate emails that were never confirmed. There are many possible reasons: 1) they thought the confirmation request was spam, so they deleted it (either manually or through an anti-spam filter). 2) they don't like the idea of having to do a stupid confirm (although no one has actually brought this up to me yet). 3) Maybe they use a reply-to or something weird that trips up TMDA (perhaps fixable or not..)
Anyway, the point is that legit emails aren't 100% getting through. The next consideration then, is to use a word-filter (and who knows, maybe TMDA does this too), to see if legit mails can be detected by their content. Maybe this could be done using a bayesian (sp?) filter, as recently discussed here, or perhaps SpamAssassin. Emails detected as legit would be delivered directly, and the sender would be auto-whitelisted. Ambiguous emails would go through the usual whitelist-confirmation procedure. This way, the word-filter never actually throws email away. It gives the sender a second chance, by sending it through the whitelist system.
This, I think, would solve the problem completely for me, as all of the legit mails that wind up unconfirmed would very much pass the legitimacy test (they mention a software project of mine, or something else very obvious). If this were in place, I could send my pending bin to
...even if you've naively left your e-mail address listed as the owner contact for your domain for years like I did. A three-pronged approach:
;-) manages to sneak through.
1) IP-level blackholing of certain large subnets, as I like many others virtually never get any legitimate email from China or Korea, and many of the craftiest fake headers ride on brand new Chinese and Korean open relays. In case of emergency, people there can always use Yahoo or the likes - and I suspect many Chinese and Koreans who communicate with people abroad are already used to doing just that, as blackholing is becoming more and more widespread.
2) RBL's. I personally use bl.spamcop.net and relays.osirusoft.com. These catch 99.2% of "quasi-legitimate" spam, and about 65% of the open-relay spam not caught above.
3) Heuristic tagging via Spam Assassin/procmail/filters/etc as a last line of defense. I personally use a filter file that I edit pretty much every time a POS (piece of spam
This is obviously more aggressive than many people can afford to be, but it's a viable solution for someone with a low signal-to-noise ratio and a high irritability ratio.
Perhaps deep down they know this, but they aren't consciously aware of it like geeks are. The mentality they approach a chatroom with is "I type, and once it scrolls off the screen, it's gone forever" whereas with a webform, they KNOW it's going into some database somewhere. The perceived threat is much lower in a chatroom, although the actual threat may be as high or higher than a webform.
Also, people tend to be a lot more paranoid about protecting their SSN, mailing address, etc than they are about their email. An email is a fairly disposable thing, and there is little threat perceived with it being public knowledge. A SSN or brick-and-mortar address is quite another thing.