how can one acquire the relevant data in cloud to carry out forensics in cloud without disturbing others data , as cloud is the common place for storing the data, and also can any one suggest me the unique tool which is used for this purpose.
If you are looking to collect real forensic data without upsetting others, why don't you set up a honeypot server? This way, you will attract a huge amount of potential attacks, and you will be able to analyse what is happening, or has happened. There are quite a number of these available to use. You can either set them up as standalone systems, or you can use one to run on the cloud. There is a good startup from around three years ago who specialise in providing a honeypot server, which has its own toolsets to track and monitor what is happening, and will allow you to amass a good deal of useful data to help you with your quest. It is Open Source, so the only cost will be the cost of your cloud instance. It is called Modern-Honey-Network, and I have included a link to their website plus a tutorial on how to set one up in Amazon EC2.
This way, you get to collect plenty of good data, and you are not likely to impact on anyone else. Besides, very few companies are willing to share forensic data resulting from a security breach or a breach attempt, so this will give you the opportunity to collect real forensic data.
Cloud computing offers utility oriented Information and Communications Technology (ICT) services to users all over the world. The evolution of Cloud computing is driving the design of data centres by architecting them as networks of virtual services; this enables users to access and run applications from anywhere in the world. Cloud computing offers significant advantages to organisations through the provision of fast and flexible ICT hardware and software infrastructures, thus enabling organisations to focus on creating innovative business values for the services they provide. As the prevalence and usage of networked Cloud computer systems increases, logically the likelihood of these systems being used for criminal behaviour also increases. Thus, this new computing evolution has a direct effect on, and creates challenges for, digital forensic practitioners working. The field of digital forensics has grown rapidly over the last decade due to the rise of the internet and associated crimes; however while the theory is well established, the practical application of the discipline is still new and developing. Law enforcement agencies can no longer rely on traditional digital forensic methods of data acquisition through device seizure to gather relevant evidence pertaining to an investigation. Using traditional digital forensic methods will lead to the loss of valuable evidential material if employed during investigations which involve Cloud based infrastructures. Cloud computing and its impact on digital forensics will continue to grow.