Google s Chrome browser is something of a tough customer for the infamous and widely deployed Blackhole Exploit Kit, according to Blue Coat security researcher, Adnan Shukor. The kit uses HTML files, instead of iframes, to redirect users to exploit pages. If the browser is detected as Internet Explorer or Firefox, then Blackhole executes its normal payload, attempting to exploit any number of Reader, Java, or Internet Explorer vulnerabilities. If a user is operating on the Chrome browser, a second redirect takes place, leading that user to fake Chrome update installer.
Source: https://threatpost.com/chrome-playing-hard-get-blackhole-exploit-kit-120612/77290/