Talktalk said that it was hit with the Mirai worm which is a malware which in October cut off access to some of the world’s best known websites, including Twitter and Spotify.
The phone outfit said that it was teaming up with several other ISPs in the UK and abroad, to try and tackle the worm.
It added that it had already made several changes to its own operations to prevent the worm’s return.
A cyberattack affecting some types of routers hit around 100,000 of Britain’s Post Office broadband customers on Sunday, the Post Office said in a statement on Thursday.
The company added: “Although this did result in service problems… no personal data or devices have been compromised. We have identified the source of the problem and implemented a resolution.”
On Tuesday, the German government and commercial security experts said hundreds of thousands of Deutsche Telekom AG customers suffered internet outages because of a worldwide attempt to hijack routing devices.