Cyphort Labs crawler monitors top sites in the world 24×7 to find cases of malicious code served via drive-by exploits. Most of the sites we see serving exploits are not compromised themselves, but redirect to advertisers poisoned by malware. This technique is called malvertising and we issued a special report on the phenomenal growth of malvertising in August of 2015.
Here is the latest update on the numbers of unique domains we have found per year:
*estimate based on the number seen so far.