Sensitive Info Goes Into ‘No Reply’ Emails Constantly. This Guy Sees It All

Cory Solovewicz receives more unwanted emails than you. Seriously—it’s a lot more. Since December 2024, one of the domains at which the security researcher receives email has registered 401,796 messages—by his calculations that’s an average of 699.99 pings per day.

This deluge isn’t the regular flood of spam, newsletters, and unwanted deals that fill many people’s inboxes. Instead, companies and other organizations are inadvertently sending Solovewicz other people’s private information and company secrets. Over the last few years, he’s received injury reports from a city government, confirmation of people’s pizza orders, and account setup emails from a school platform. “I get service orders for people that need repairs. I get lots of test platform credentials,” says Solovewicz, a security researcher and consultant.

Solovewicz is receiving the avalanche of messages as he’s the owner of the domains noreply.us and noreply.net, which he purchased in 2020 and 2024, respectively. After originally planning to use the noreply.us domain as a catch-all email—which receives mail sent to any @ address on that domain—to filter messages and enhance his privacy, the researcher quickly noticed that other systems were sending mail to @noreply.us addresses. “I created an accidental honeypot,” Solovewicz tells WIRED. “I had no idea it was going to turn into this.”

Companies may send emails to [companyname]@noreply.net or similar variations believing they aren’t going anywhere, or could not be monitored in any way. Broadly it’s also possible that they may transform a person’s individual email address to send to one of these placeholder style domains if someone leaves a company or deletes their account.

What started out as a personal email project has become a large-scale effort to warn businesses and other groups that they have misconfigured their internal systems and are accidentally sharing sensitive information. Solovewicz, who presented his work at the Defcon security conference yesterday, says ultimately he is relieved that he ended up with the domains rather than criminal hackers or nation states who could use the data maliciously.

“I did not realize that this was going to be as big of a problem as it is,” says Solovewicz, who is not publicly naming impacted entities. The researcher has been alerting affected companies of their problems, encouraging them to fix the errors and misconfigurations. “I just want companies and organizations to do the right thing and to be auditing their systems and fixing their stuff.”

Solovewicz says that the noreply.net domain is the largest he owns and has received 400,000 messages over the year and a half that he’s owned it, with 28,365 of those containing attachments. The noreply.us domain has been sent 37,255 messages over 2,345 days since he purchased it in 2020. Over the month before his conference talk, combined, they’ve received more than 11,000 messages. Overall, emails have been sent from more than 14,000 “from” addresses, from 6,200 root domains. The messages are automated by company systems, not written by humans, the researcher says.

While the issue is not a new one—almost 20 years ago, independent security journalist Brian Krebs, then working at the Washington Post, wrote how companies were sending millions of messages to @donotreply.com emails—it is inherently avoidable. For instance, companies could use internal domains or the .invalid domain that is guaranteed not to exist.

Solovewicz is not alone in this voluntary endeavor, which is helping protect the data of companies—often large ones. Earlier this year, Mike Sheward, the head of security at EV charging company Xeal, spent around $15 to buy the domain deleteduser.com. “Within the first hour, there were three different organizations that had emailed stuff to @deleteduser.com,” Sheward tells WIRED, pointing out that companies appear to be simply changing email addresses rather than entirely deleting accounts from their systems.