The deal also gives Symantec access to the hundreds of millions of customers who use Yahoo services and helps the software maker fend off Microsoft, which is making a big push into the potentially lucrative consumer security market.
For Yahoo, the offering helps assure customers that the Internet is a secure place to do everything from banking to travel planning to job searches as it battles against Google and Microsoft to be the dominant Internet services provider, the companies said.
"Internet security is important to our Yahoo users and by working with Symantec, we are bringing the comfortable security blanket that their Norton brand services provide to consumers," said Stephen Miller, director, product management, Yahoo.
Yahoo and Symantec said they will market the co-branded Norton Internet Security service throughout the Yahoo network, which includes Yahoo Mail, Yahoo Toolbar and Yahoo Search, and other online services.
In addition, Symantec will also offer Norton Spyware scan for the Yahoo Toolbar and a co-branded toolbar that offers more direct links to other security tools. It will also offer its antivirus and online firewall protections on Yahoo's Online Protection for broadband users.
Yahoo users can sign up for Norton Internet Security, which blocks spam, viruses and unwanted adware, for a free 30 day trial and then purchase a 12-month subscription for $49.99, the companies said. The price is a $20 discount for Yahoo users.
Symantec, the world's largest security software service, already offers antivirus scanning for Yahoo e-mail users. The company also has a partnership deal with Google that makes it one of the Internet search provider's preferred software vendors as part of its recommended PC set up.