Around 3.3 million servers are running POP3/IMAP email services without encryption (TLS) enabled, the Shadowserver Foundation, a nonprofit security organization, has discovered. Most of these servers reside in the US, Germany, and Poland.
POP3 (Post Office Protocol version 3) is an aging protocol used by email clients to retrieve emails from a mail server. It is often used alongside the newer protocol IMAP (Internet Message Access Protocol).
By infosecbulletin
/ Monday , October 5 2026
Citrix has put out emergency security updates for a NetScaler SAML flaw that hackers are using. Known as CVE-2026-88779, this...
Read More
By infosecbulletin
/ Monday , October 5 2026
Hackers got into the identity and access management system at the Technical University of Denmark (DTU) and downloaded a lot...
Read More
By infosecbulletin
/ Sunday , October 4 2026
Microsoft's official X account was taken over to promote an unapproved Clippy-themed cryptocurrency. The tech giant’s X account, with 13...
Read More
By infosecbulletin
/ Saturday , October 3 2026
CPanel has put out security updates to fix three problems in cPanel & WHM. These problems could let attackers take...
Read More
By infosecbulletin
/ Friday , October 2 2026
Nearly 100,000 Bee Cheng Hiang customers had their email addresses leaked when an employee used an AI tool to generate...
Read More
By infosecbulletin
/ Thursday , October 1 2026
Hackers to exploit a flaw in Zimbra mail servers that are connected to the Internet. They send special emails that...
Read More
By infosecbulletin
/ Wednesday , September 30 2026
Google has said that hackers are using two serious Citrix NetScaler security holes to get root access, set up hidden...
Read More
By infosecbulletin
/ Wednesday , September 30 2026
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) is alerting people about a major flaw in MikroTik RouterOS. This could...
Read More
By infosecbulletin
/ Tuesday , September 29 2026
Apple has launched iOS 26.7.1 and iPadOS 26.7.1 to fix a serious zero-day flaw that it believes might have been...
Read More
By infosecbulletin
/ Tuesday , September 29 2026
The JadePuffer ransomware group is attacking Azure users with agent-based attacks that gather information, steal passwords, and damage key components. The...
Read More
The Shadowserver Foundation tracks 3.3 million POP3/IMAP servers along the globe that do not have TLS encryption.

“It’s time to retire those services!” the organization warns.
“We have started notifying about hosts running POP3/IMAP services without TLS enabled, meaning usernames/passwords are not encrypted when transmitted. We see around 3.3M such cases with POP3 & a similar amount with IMAP (most overlap).”
Almost 900,000 of these servers are from the US, while Germany follows in second place with 523,000 servers. Poland and Japan are next on the list, with 381,800 and 301,800 unprotected servers, respectively.
Users of such email services should be aware that anyone with basic network monitoring tools can intercept their communications and steal their credentials.
“Note that regardless of whether TLS is enabled or not, service exposure may enable password-guessing attacks against the server,” the Shadowserver Foundation said.