Dive Brief:

• Across popular sites like Amazon, YouTube, and Yahoo, Cisco Systems is warning users to be aware of malicious advertisements. 
• The ad network —nicknamed "Kyle and Stan" —includes over 700 malicious domains that allow it to set up spyware, malware, and browser hijacks on both Windows and Apple OS X. 
• Victims that click on the ads are redirected and to a download of a piece of malware — usually disguised as a media player or some other software. 

Dive Insight: 

This wouldn't be the first time a malicious software was distributed through ads, but the sheer size and scope of the Kyle and Stan network is unsettling. The ads are appearing on mainstream, trusted websites which makes it harder for the ads to raise red flags for site visitors.