Comcast Corp. said Thursday that hackers took over and defaced its Web portal for several hours overnight and prevented users from accessing Web mail and account records on the company's site.

The homepage of was down between 11 p.m. Eastern time Wednesday and 12:30 a.m. Thursday where visitors were greeted with either a Site under construction message or a cryptic note reading: KRYOGENIKS EBK and DEFIANT RoXed COMCAST sHouTz To VIRUS Warlock elul21 coll1er seven.

Comcast spokeswoman Jennifer Khoury said Thursday that the hijacking had been reversed in the morning, but there was still a possibility that some customers may still be unable to access and its Web-based e-mail.

The hackers somehow received access to passwords to alter domain-name registration information with Comcast's registrar, Network Solutions, said Susan Wade, a Network Solutions spokeswoman. The hackers were then able to switch the DNS (Domain Name System) servers associated with and redirect Internet traffic to their own server. They also added offensive comments to the record.

It is not known how the hackers gained access to Comcast's Network Solutions account.