Cloud computing has many advantages so it's not surprising that it has become so popular with the even the biggest online services using cloud providers for their infrastructure. However, many in security have pointed out that the "cloud" could perhaps also be termed "somebody else's computer", which immediately rings alarm bells from a security perspective. Hidden in there is a fact that has been troubling researchers for some years: cloud computing means shared computing so you are using the same hardware as others running their systems.
Back in 2009 researchers began publishing work that seemed to show that it was possible for data to "leak" from one system to another when using shared hardware. Papers such as these particularly highlighted the dangers of shared cache memory. Side channel attacks were described in papers such as "Hey, You, Get Off of My Cloud: Exploring Information Leakage in Third-Party Compute Clouds" that showed just how data could be exfiltrated from a system by an attacking systems that was co-resident on the same hardware.
