Thousands of Demon passwords exposed by error
Demon Internet has confirmed that a rogue Excel spreadsheet attachment exposed thousands of customer details.
Demon Internet has suffered an embarrassing data protection failure, after an email sent to customers attached a spreadsheet with the personal details of more than 3,600 customers.
Demon, which serves both homes and businesses, confirmed that the customer information of a number of customers signed up to Demon's new paperless billing platform had been circulated, in error, as an email attachment.
Sister site PC Pro said it contained the full name of the customers, email addresses, telephone numbers and the names of the customers' businesses, with police forces and NHS trusts among the email addresses listed.
In a statement from Demon Internet's parent company Thus, the incident was blamed on "human error", but it was made clear that the spreadsheet did not contain any financial or payment information.
"On discovery, Demon took immediate steps to secure the information and security of customers affected, by changing all affected customer usernames and passwords," the statement read.
"We can confirm categorically that no customer accounts were accessed inappropriately during this time," it added.
The company apologised and said it would review all processes and procedures to ensure that the incident wouldn't be repeated.
Sign up today and you will receive a free copy of our Future Focus 2026 report - the leading resource for IT decision-maker insight on priorities and investment areas in AI, security and more.
-
1Password teams up with Anthropic to give Claude access to your credentialsNews A new ‘zero-exposure’ security framework allows agents to use stored credentials in the 1Password vault
-
We need to do something about passwordsPasswords are a fundamental aspect of access security, but recent password leaks have undermined their ability to protect data
-
Dashlane lifts the lid on attack that saw hackers download encrypted user vaultsNews The company said it has now informed all affected customers, and taken action to shut down the operation
-
The NCSC says it’s time to switch to passkeysNews UK security organization calls for companies to step up and offer more secure ways to login
-
AI agents are creating new identity security risks: 1Password wants to solve thatNews The Unified Access system from 1Password will help enterprises manage AI agent access across different devices and users
-
Using AI to generate passwords is a terrible idea, experts warnNews Researchers have warned the use of AI-generated passwords puts users and businesses at risk
-
Researchers called on LastPass, Dashlane, and Bitwarden to up defenses after severe flaws put 60 million users at risk – here’s how each company respondedNews Analysts at ETH Zurich called for cryptographic standard improvements after a host of password managers were found lacking
-
Thousands of exposed civil servant passwords are up for grabs onlineNews While the password security failures are concerning, they pale in comparison to other nations

