The Black Hole exploit kit and the Carberp Trojan have a lovely, symbiotic relationship. In November, infections by the Trojan tripled overall from the month before. Attackers are using sites that have previously been infected with Black Hole as launching points for drive-by download attacks against visitors. Java vulnerabilities in Java are easier and more consistently exploitable than those in PDF and SWF. Recent attacks on Java have far outpaced attacks against vulnerabilities in any other piece of software in the last year.
Source: https://threatpost.com/carberp-and-black-hole-exploit-kit-wreaking-havoc-120511/75957/