News for hackers. Stuff that matters.
Re:Complexities of e-mail validation logic by rootusrootus on Monday May 24, 2021 @11:27AM (#27265487)
> So I'll use [email protected] when signing up at Amazon

I go a little farther. I figure an attentive spammer might figure out that if I use [email protected] to sign up for Amazon, I may have exactly the scheme where *@johnsmith.net will work, so they can just add that to the spam list as a wildcard and pick a new address every time. So instead, I use [email protected], john102, john103, etc, to try and obscure my strategy and prolong the life of the domain forwarding.

Re:Complexities of e-mail validation logic by typicalbender on Monday May 24, 2021 @12:58PM (#27266781)
Hard truth is you're not worth enough for a spammer to look for that pattern, it's a numbers game and you're just making it harder on yourself.

Also unless you're keeping a lookup table you're losing a great benefit of the wildcard. You can, and I have caught a few places, tell when a company sells your email. If I get an email from company XYZ to my email [email protected] I know exactly who sold my email and to whom.

Re:Complexities of e-mail validation logic by rootusrootus on Monday May 24, 2021 @01:34PM (#27267282)
I agree that I'm probably not worth the effort, but if this kind of domain wildcard strategy were to become more popular it is entirely feasible for a rudimentary machine learning algorithm to detect its use.

> unless you're keeping a lookup table you're losing a great benefit of the wildcard

That's true, I don't keep a lookup table per se, though I do have a deleted items folder that I could look back in. I'm not sure what I would do, though, if I knew what particular company sold my email address? Send them a nastygram they will just ignore? I just block the address and move on.

Re:Complexities of e-mail validation logic by labawi on Tuesday May 25, 2021 @04:09PM (#27281940)
I think a typical spammer doesn't care much about such users, but if given given a choice they would rather avoid such users.

AFAIU, most buld spam is targeted on gullible or vulnerable people. The spam is often terrible on purpose.

Sophisticated or targeted attacks are a different category and they may be a good reason to prefer something non-guessable.

Re:Complexities of e-mail validation logic by willcipriano on Monday May 24, 2021 @11:33AM (#27265548)
I just have a entire domain for the purposes of spam. Anything sent to there ends up in my bulk folder. I use [email protected] so I can tell who sells my email or gets hacked. Never noticed someone trying to send a email to any addresses I haven't previously used.
Re:Complexities of e-mail validation logic by wastholm on Monday May 24, 2021 @11:59AM (#27265928)
> Never noticed someone trying to send a email to any addresses I haven't previously used.

At least a few years ago, I noticed a lot of spam to <random first name>@<my domain> -- i.e., completely made-up addresses that I had never used. Since messages sent to those addresses were guaranteed to be spam, I started treating them as free training data for the spam filter.

I don't know if this still happens, though, because I haven't looked.

Re:Complexities of e-mail validation logic by Grollicus on Monday May 24, 2021 @12:19PM (#27266199)
This is currently happening to my email domain. Gets rejected as it doesn't have a valid hash (recipient name), but the logfiles are full of <3 letters>@mydomain.com and <english_word>@mydomain.com rejections.
Re:Complexities of e-mail validation logic by klyrs on Monday May 24, 2021 @12:37PM (#27266457)
Yeah, this is an age-old issue -- in the early 00s, my mom got a domain and used the email <first_initial>@<domain>.com. She gave up battling the deluge of spam after about a year. We looked through the logs, and saw that her next choice of handle was also getting tons of spam, too, because it was also short.
Re:Complexities of e-mail validation logic by batch12 on Monday May 24, 2021 @02:54PM (#27268300)
I do the same thing. I use [email protected]. The addresses are temporary if I want them to be and I can automatically lock the senders to a list that is either automatically learned after x days or manually curated. I've seen some 'marketing' mail get filtered but no hacks yet.
Re:Complexities of e-mail validation logic by cgriswald on Monday May 24, 2021 @04:07PM (#27269077)
I’ve got [email protected] email for my domain and I’ve never created such an account, much less given it out. Without some uniqueness in the username, I’m not sure you can tell a company sold or lost your data.
Re:Complexities of e-mail validation logic by bcrosby95 on Monday May 24, 2021 @12:45PM (#27266579)
Spamming is a numbers game. I kinda doubt enough people are using this scheme to make figuring this out worthwhile for a spammer.
Re:Complexities of e-mail validation logic by nerdponx on Monday May 24, 2021 @12:20PM (#27266231)
I've wondered about this with big companies like Facebook, Google, Amazon, etc. as well as behind-the-scenes spyware/ad firms who are all probably very interested in linking my identity across user accounts, email addresses, device fingerprints, etc. I've hoped that there aren't enough people doing it (yet) for these orgs to find it worth the effort.
Re:Complexities of e-mail validation logic by macNchz on Monday May 24, 2021 @12:59PM (#27266804)
There very much are companies doing this and selling it as a service...here's an API that you can query with a piece of contact information to retrieve all sorts of additional information, including hashes of alternate email addresses, mobile device ids, social media profiles, and plenty of other stuff: https://platform.fullcontact.com/docs/apis/enrich/person-ins...
Re:Complexities of e-mail validation logic by rootusrootus on Monday May 24, 2021 @01:39PM (#27267339)
At a certain point -- probably the moment it becomes a business unto itself -- this kind of data collection should be subject to all the same rules we've come up with for credit bureaus. It should be a legal requirement that I can get the entire profile they have built for me.
Re:Complexities of e-mail validation logic by nerdponx on Monday May 24, 2021 @03:11PM (#27268491)
I was wondering specifically if they have special cases to identify such "personal" email domains and use them for record linkage.

It seems like an obvious thing to try, but maybe not worth the effort of implementing it, given the high risk of false positives and the low % of people who actually do stuff like this (not to mention they're probably not people who click on ads anyway).

Re:Complexities of e-mail validation logic by rootusrootus on Monday May 24, 2021 @01:37PM (#27267304)
Given the sheer amount of money involved, I believe it is likely that there are players in the market who are far more capable than we give them credit for.
Re:Complexities of e-mail validation logic by licebmi__at__ on Monday May 24, 2021 @02:19PM (#27267848)
I kinda imagine that spammer go for low hanging fruit. So spammers won’t bother with defeating a catchall domain forwarding, as it’s unlikely to give them returns. Although a motivated attacker might decide to try to send interesting phishing.
Re:Complexities of e-mail validation logic by dhruvrrp on Monday May 24, 2021 @07:38PM (#27270991)
What do you use for email hosting? Ive tried to do something similar but most places have a limit for email addresses even with paid plans.
Re:Complexities of e-mail validation logic by SilverRed on Monday May 24, 2021 @09:51PM (#27271839)
Fastmail does not seem to have any limit listed. I have not tested any extreme case since I just use a wildcard.