Google, Apple, eBay and Yahoo were among almost 300 sites affected by a hack attack in Pakistan.
The hack targeted sites that had Pakistani domain names, such as .com.pk, .pk and org.pk.
Hackers exploited an apparent vulnerability in domain name systems, redirecting visitors of popular sites to a different site.
The page featured a picture of two penguins walking across a bridge with the slogan "Pakistan Downed".
The companies themselves were not breached, but it meant key services, such as Google's Gmail, were temporarily down.
The motive for the attack is not known, with many suggesting the hack was carried out to simply highlight weaknesses in systems maintained by PKNIC, the organisation which administers .pk web domains.
PKNIC told the BBC it would be releasing a statement about the attack "soon".
Technology blog ProPakistani said it had received an email from the hackers explaining how they carried out their attack. The perpetrators appear to be of both Pakistani and Turkish origin.
ProPakistani said it would share the information with PKNIC "if they want to resolve the flaws".
It is believed that all of the domains were registered by MarkMonitor, a firm that offers brand protection for companies online by buying up related domains in countries around the world.
When contacted by the BBC, a Markmonitor spokesman said he "unfortunately cannot comment on specific security incidents".