Researchers Find New Approach to Attacking Cloud Infrastructure

Public cloud infrastructure presents security teams with a new invisible management layer, creating new security challenges that demand better understanding. Many organizations don't properly understand the cloud identity and access management layer and often fail to secure it.

Such misunderstandings usually lead to dangerous misconfigurations that can drive customer risk; for example, in the case of the recent Capital One breach. Current security practices and controls are not sufficient to mitigate the risk posed by misunderstanding of the public cloud, explain Igal Gofman, XM head of security research, and Yaron Shani, XM senior security researcher.

When Gofman and Shani began to research cloud-focused threats, they realized many popular defense mechanisms focus on specific attack vectors: for example, brute force protections against cloud services and applications like password spray tools or AWS recon tools. Post-breach defense is usually based on different user activities and machine learning algorithms.

"The missing link in this approach is that those mechanisms are usually defensive in nature and usually not predictive," the researchers explain in an interview with Dark Reading. Traditional protections primarily focus on network, application, and operating system defense, they say.

A new attack vector exists in cloud providers' application programming interfaces (API), which are accessible through the Internet and give adversaries an opportunity to take advantage and gain highly privileged access to critical assets in the cloud. The people in charge of managing cloud resources are usually members of the DevOps, development, and IT teams, who gain access to APIs using different software development kits and dedicated command line tools.

"Once those account credentials are compromised, gaining access to high-value resources is trivial," the researchers say. Even if an organization makes a private subnet not open to the Internet, they add, cloud APIs can be easily accessed from the Internet with the right API key. Cloud provider tools—for example, the command-line interface tool (CLI) — save the user's credentials inside a file, which is typically locally stored on the individual's workstation.

At this year's Black Hat Europe, Gofman and Shani plan to demonstrate an alternative new approach to attacking cloud infrastructure in a talk titled "Inside Out — The Cloud Has Never Been So Close." Their methodology involves using a graph to show permission relationships between different entities, revealing risky choke points that need to be addressed and eliminated. The outcome of this graph, they say, can be used by red and blue teams to gain deeper understanding of permission relationships in cloud environments. After explaining the connections, they'll show how attackers can abuse features to gain privileges.

Attackers don't need to be sophisticated to take advantage of public cloud APIs, they say, noting they didn't find any open-source tools that automate the entire stack of the research.

"In practice, the sophistication required to develop such tools is not high, because basically all the information is publicly available and well-documented by most cloud providers, meaning they document each security feature in great detail and it can serve both the defenders and the adversaries," Gofman and Shani say. In general, they continue, developing an offensive tool that leverages their attack research would be easier than building a defensive system around it.

In terms of protecting themselves, the first and most important steps companies should follow are best practice guides from cloud providers, the researchers say. Large and complex organizations often have trouble tracking and monitoring permissions in large cloud infrastructures, and evaluating general organizational risk factors, they explain. They suggest constantly monitoring paths attacks can take to high-value cloud resources.  

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