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Pentesting the Cloud
Several months ago, I attended an industry conference where there was much buzz about “The Cloud.” A couple of the talks purportedly addressed penetration testing in the Cloud and the difficulties that could be encountered in this unique environment; I attended enthusiastically, hoping to glean some insight that I could bring back to NetSPI and help to improve our pentesting services. As it turns out, I was sorely disappointed. In these talks, most time was spent noting that Cloud environments are shared and, in executing a pentest against such an environment, there was a substantially higher risk of impacting other (non-target) environments. For example, if testing a web application hosted by a software-as-a-service (SaaS) provider, one could run the risk of knocking over the application and/or the shared infrastructure and causing a denial of service condition for other customers of the provider in addition to the target application instance. This is certainly a fair concern but it is hardly a revelation. In fact, if your pentesting company doesn’t have a comprehensive risk management plan in place that aims to minimize this sort of event, I recommend looking elsewhere. Also, the speakers noted that getting permission from the Cloud provider to execute such a test can be extremely difficult. This is no doubt due to the previously mentioned risks, as well as the fact that service providers are typically rather hesitant to reveal their true security posture to their customers. (It should be noted that some Cloud providers, such as Amazon, have very reasonable policies on the use of security assessment tools and services.) In any case, what I really wanted to know was this: is there anything fundamentally different about testing against a Cloud-based environment as compared with testing against a more traditional environment? After much discussion with others in the industry, I have concluded that there really isn’t. Regardless of the scope of testing (e.g., application, system, network), the underlying technology is basically the same in either situation. In a Cloud environment, some of the components may be virtualized or shared but, from a security standpoint, the same controls still apply. A set of servers and networking devices virtualized and hosted in the Cloud can be tested in the same manner as a physical infrastructure. Sure, there may be a desire to also test the underlying virtualization technology but, with regard to the assets (e.g., databases, web servers, domain controllers), there is no difference. Testing the virtualization and infrastructure platforms (e.g., Amazon Web Services, vBlock, OpenStack) is also no different; these are simply servers, devices, and applications with network-facing services and interfaces. All of these systems and devices, whether virtual or not, require patching, strong configuration, and secure code. In the end, it seems that penetration testing against Cloud environments is not fundamentally different from testing more conventional environments. The same controls need to exist and these controls can be omitted or misapplied, thereby creating vulnerabilities. Without a doubt, there are additional components that may need to be considered and tested. Yet, at the end of the day, the same tried and true application, system, and network testing methodologies can be used to test in the Cloud.
