Yahoo has confirmed that it is meeting with the FBI to investigate the malicious attack which closed down many of its services in the US and Europe on Monday.
The Internet service provider said, however, that it is unlikely to be affected financially by the co-ordinated, distributed denial-of-service attack because it rescheduled advertising to other parts of its portal.
A Yahoo spokesman said the company would be "discussing the appropriate next steps" in tracking down the people responsible for a near shutdown of its service.
Yahoo stressed that its systems had not been hacked into and that all its customer information remains secure.
The attack is believed to have originated from 50 different Internet protocol addresses. Up to 1Gb of requests per second flooded Yahoo's routers, which is more than many websites receive in a year.
Yahoo managed to install a filter to stop the so-called fake traffic jamming its system after the attack. The portal had resumed normal services by yesterday.
Yahoo was not the only site to be crippled by a malicious attack this week. Ebay and Buy.com were also hit yesterday and had to be shut down intermittently.
Cotton seedling freezes to death as Chang'e-4 shuts down for the Moon's 14-day lunar night
Fortnite easily out-earns PUBG, Assassin's Creed Odyssey and Red Dead Redemption 2 in 2018
Meteor showers as a service will be visible for about 100 kilometres in all directions
Saturn's rings only formed in the past 100 million years, suggests analysis of Cassini space probe data
New findings contradict conventional belief that Saturn's rings were formed along with the planet about 4.5 billion years ago