More than 300,000 users per hour were being redirected to malicious websites serving 'Magnitude Exploit Kit', that exploits vulnerabilities in Java and installs a variety of different malware i.e.
- Advertisement clicking malware
"It is unclear which specific group is behind this attack, but the attackers are clearly financially motivated,"
Based on the same sample, the countries most affected by the exploit kit are Romania, Great Brittain and France. At this time it’s unclear why those countries are most affected, it is likely due to the configuration of the malicious advertisements on Yahoo.
To protect yourself, you can use "Adblock" extension for Firefox, Safari and Chrome browsers that can block advertisements on webpage.