Malware taking a bit(coin) more than we bargained for  Amir
Fouda Microsoft    download slides (PDF)  Social and
technological change often creates new opportunities for
positive change. Unfortunately, it also means more opportunities
for crime. So, when a new system of currency gains acceptance
and widespread adoption in a computer-mediated population, it is
only a matter of time before malware authors attempt to exploit
it. As of half way through 2011, we started seeing another means
of financial profiteering being perpetrated by the malware
authors; they started targeting Bitcoins.  Bitcoin mining and
stealing functionality has been discovered in a number of the
most notable and prevalent malware families, including Alureon,
Sirefef and Kelihos. Notably, Bitcoin being open-sourced
software means that Windows users are not the only target.
Cross-platform attacks have already been seen, with OS X threats
such as MacOS_X/DevilRobber.A emerging on the scene in October
2011.  The very nature of the way Bitcoin