Researchers at the University of California, San Diego (UCSD) and the Massachusetts Institute of Technology (MIT) have found security holes in Amazon's EC2 cloud-computing service. The researchers were able to execute basic versions of side-channel attacks, in which a hacker looks at indirect information related to the computer to determine what is taking place on the machine. The researchers succeeded in pinpointing the physical servers used by programs running on the EC2 cloud, and then extracted small amounts of data from those programs. Previous research has demonstrated the vulnerability of side-channel attacks. In 2001, University of California, Berkeley researchers were able to extract password information from an encrypted SSH data stream by performing a statistical analysis of how keystrokes generated traffic on the network. By looking at the computer's memory cache, the UCSD and MIT researchers were able to obtain basic information about when other users on the same machine were using a keyboard to perform tasks such as accessing the computer using an SSH terminal. The researchers say that measuring the time between keystrokes enables them to determine what is being typed on the machine. To perform this attack, the researchers had to determine which EC2 machine was running the program they wanted to target, a difficult challenge as cloud computing is supposed to hide this information. However, by performing an analysis of DNS traffic and using a network-monitoring tool, the researchers developed a technique that could provide a 40 percent chance of placing their attack code on the same server as their target. Security experts say that side-channel techniques could lead to more serious problems for cloud computing.
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