Much have been said about futility of trying to validate email addresses. Generally accepted advice is that you should just send verification link and don’t care about trying to validate it beforehand.
But what if you were really hell-bent on having validation step, and at the same time follow the advice? Apparently some people decided they could to it by… sending spam.
Take this Pangram sign-up form. Filling email field here will perform this request:
curl --request POST --data '{"email": "example@example.com"}' https://www.pangram.com/api/validate-email
And soon enough, without doing anything else, you will get an mysterious email. Whaaa…?
Date: Tue, 23 Jun 2026 15:29:10 +0000
From: "Winwin Insights" <aliyah@sifgoldenshine.com>
To: <example@example.com>
Reply-To: <aliyah@sifgoldenshine.com>
Subject: Fact of the day: Magnetic
Message-ID: <2111VQOY773L9P98LN32@sifgoldenshine.com>
Precedence: Bulk
MIME-Version: 1.0
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: base64
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Like every self-respecting spam sender, they rotate through many sender domains (not exhaustive!):
apiaryapiaries.com
avaspaintinggallery.com
bonfirebeat.com
catnipblissfulhaven.com
chloesgardeninghaven.com
classmerge.com
endurovistawear.com
fragjoystick.com
gainswiftwave.com
ghostlygourd.com
hydroponicseeders.com
lanternlyric.com
mangomysticfusion.com
northchronicle.com
pasturelandplough.com
platformerboss.com
pyxisvoyager.com
raisetyrvalor.com
rockandrender.com
ryeirrigator.com
sifgoldenshine.com
sipandsweater.com
storybookstage.com
strategycrit.com
thruwaymotors.com
tillageacre.com
venusbases.com
But unlike typical spammer, they really go to the extra mile trying to get their spam delivered, immediately retrying from different servers when rejected (apparently some of their IPs are listed on DNSBLs. hmm, I wonder why…):
Jun 23 16:15:36 milek7.pl postfix/smtpd[404910]: connect from mta2.icicleglimmerfrost.com[31.133.27.229]
Jun 23 16:15:38 milek7.pl postfix/smtpd[404910]: NOQUEUE: reject: RCPT from mta2.icicleglimmerfrost.com[31.133.27.229]: 554 5.7.1 Service unavailable; Client host [31.133.27.229] blocked using spam.spamrats.com; SPAMRATS IP Addresses See: http://www.spamrats.com/bl?31.133.27.229; from=<lyla@icicleglimmerfrost.com> to=<example@example.com> proto=ESMTP helo=<mta2.icicleglimmerfrost.com>
Jun 23 16:15:39 milek7.pl postfix/smtpd[404910]: disconnect from mta2.icicleglimmerfrost.com[31.133.27.229] ehlo=2 starttls=1 mail=1 rcpt=0/1 quit=1 commands=5/6
Jun 23 16:15:39 milek7.pl postfix/smtpd[404910]: connect from mailc.plowdairy.com[93.120.120.78]
Jun 23 16:15:40 milek7.pl postfix/smtpd[404910]: NOQUEUE: reject: RCPT from mailc.plowdairy.com[93.120.120.78]: 554 5.7.1 Service unavailable; Client host [93.120.120.78] blocked using b.barracudacentral.org; http://www.barracudanetworks.com/reputation/?pr=1&ip=93.120.120.78; from=<august@plowdairy.com> to=<example@example.com> proto=ESMTP helo=<mailc.plowdairy.com>
Jun 23 16:15:41 milek7.pl postfix/smtpd[404910]: disconnect from mailc.plowdairy.com[93.120.120.78] ehlo=2 starttls=1 mail=1 rcpt=0/1 quit=1 commands=5/6
Jun 23 16:15:41 milek7.pl postfix/smtpd[404915]: connect from servidor.classmerge.com[176.113.182.193]
Jun 23 16:15:43 milek7.pl postfix/smtpd[404915]: 53EB982421: client=servidor.classmerge.com[176.113.182.193]
Jun 23 16:15:43 milek7.pl postfix/cleanup[404918]: 53EB982421: message-id=<BY7HI0WM9LDYW2J4J2KQ@classmerge.com>
Jun 23 16:15:43 milek7.pl postfix/qmgr[404883]: 53EB982421: from=<sage@classmerge.com>, size=1301, nrcpt=1 (queue active)
Jun 23 16:15:43 milek7.pl postfix/lmtp[404919]: 53EB982421: to=<me@milek7.pl>, orig_to=<example@example.com>, relay=milek7.pl[dovecot/lmtp], delay=1.8, delays=1.7/0.03/0.05/0.03, dsn=2.0.0, status=sent (250 2.0.0 <me@milek7.pl> dvDAJS+xOmq4LQYA8NhtAw Saved)
Jun 23 16:15:43 milek7.pl postfix/qmgr[404883]: 53EB982421: removed
Jun 23 16:15:44 milek7.pl postfix/smtpd[404915]: disconnect from servidor.classmerge.com[176.113.182.193] ehlo=2 starttls=1 mail=1 rcpt=1 data=1 quit=1 commands=7
This is all extremely dumb, because either you “validated” addresses by delivering spam to them, or if destination does content filtering you get your spam rejected and “validation” fails.
Now I’m really curious how they managed to come up with this, because it seems it took an awful lot of effort to do this. I’m guess there’s some stupid SaaS for “validating” email, through it would be funny if it turns out that some LLM agent went off rails.
(actual transactional mails from Pangram are sent through Mailgun)
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