Internet and e-mail policy and practice
including Notes on Internet E-mail


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Home :: Email

31 Oct 2014

Different kinds of spam Email

Someone was asking who has the largest set of spamtraps; I opined that nobody knows, since the people will the biggest ones don't discuss the details. Also, it's not a very useful metric. There are spammers who only send to specific large ISPS, so, say, Google would know all about them, and other people wouldn't see them at all.

Also, different kinds of spamtraps get different kinds of spam. I have three general kinds:

  • Addresses that were never valid, typically invented by broken scrapeware that grabbed message IDs or mangled addresses from web sites
  • Abandoned addresses and domains, that may have been valid a decade or more ago, but only get spam now
  • A depressingly large number of addresses given to well-known companies who then leaked them to spammers.

I also get a fair amount to real addresses that aren't spamtraps, but that are caught by filters or by hand.

I haven't analyzed the spam profiles in detail but they're clearly different. For example, one ESP doesn't appear on most people's spam radar, but they send me a great deal of spam (relative to my overall modest volume.) That appears to be because they have a lot of poor quality lists with repurposed addresses, from senders booted from more selective ESPs, and they're constantly hitting role addresses that aren't spamtraps, but should never be on anyone's lists.


posted at: 00:03 :: permanent link to this entry :: 0 comments
Trackback link is http://jl.ly/Email/spamflavor.trackback

08 Oct 2014

How can we do spam filtering on mail we can't read? Email
For reasons that should be obvious, a lot of people are thinking about ways to make e-mail more secure, and harder to spy on. The most likely scenario is an improved version of PGP or S/MIME, two existing encrypted mail systems, that let people publish their encryption key, which correspondents use to encrypt mail so that only the recipient can read it. While this is a significant improvement in privacy, it has the problem that spam filters at the ISP can't read the mail either.

See more ...


posted at: 23:36 :: permanent link to this entry :: 0 comments
Trackback link is http://jl.ly/Email/cryptospam.trackback

16 Jul 2014

The mail forwarding threat model Email
The recent
DMARC kerfluffle has brought new attention to mail forwarders that send mail on behalf of other people. We've been giving a lot of thought to ways to tell nice forwarders from nasty ones, so that mail systems can deliver mail from the nice ones and filter the nasty ones. It occurs to me that there are several scenarios for the way that forwarders work, so I've collected them in a little chart.

See more ...


posted at: 19:42 :: permanent link to this entry :: 0 comments
Trackback link is http://jl.ly/Email/fwdthreat.trackback

03 Jun 2014

Dealing with DMARC Email

DMARC is an anti-phishing scheme that was repurposed in April to try to deal with the fallout from security breaches at AOL and Yahoo. A side effect of AOL and Yahoo's actions is that a variety of bad things happen to mail that has From: addresses at aol.com or yahoo.com, but wasn't sent from AOL or Yahoo's own mail systems. If the mail is phish or spam, that's good, but when it's mailing lists or a newspaper's mail-an-article, it's no so good.

The mailing list community has been gnashing its teeth for the past month trying to figure out the least bad ways to deal with the problem.

To keep track of all the ways of avoiding or limiting the damage, I've made a page on the ASRG wiki. (The ASRG is gone, but the wiki lives on.)

If I've missed anything, let me know and I'll update it.


posted at: 23:26 :: permanent link to this entry :: 0 comments
Trackback link is http://jl.ly/Email/undmarc.trackback

28 Apr 2014

A helpful tip for AOL users Email
AOL finally
confirmed today that crooks have stolen credentials and address books from some large number of AOL users. (They say 2%, but that's only the ones they know about so far.) So we suggest you take some routine security precautions.

See more ...


posted at: 21:57 :: permanent link to this entry :: 0 comments
Trackback link is http://jl.ly/Email/aolchange.trackback

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