T1535 - Unused/Unsupported Cloud Regions

Adversaries may create cloud instances in unused geographic service regions in order to evade detection. Access is usually obtained through compromising accounts used to manage cloud infrastructure.

Cloud service providers often provide infrastructure throughout the world in order to improve performance, provide redundancy, and allow customers to meet compliance requirements. Oftentimes, a customer will only use a subset of the available regions and may not actively monitor other regions. If an adversary creates resources in an unused region, they may be able to operate undetected.

A variation on this behavior takes advantage of differences in functionality across cloud regions. An adversary could utilize regions which do not support advanced detection services in order to avoid detection of their activity.

An example of adversary use of unused AWS regions is to mine cryptocurrency through Resource Hijacking, which can cost organizations substantial amounts of money over time depending on the processing power used.(Citation: CloudSploit - Unused AWS Regions)

Atomic Tests:

Currently, no tests are available for this technique.

Detection

Monitor system logs to review activities occurring across all cloud environments and regions. Configure alerting to notify of activity in normally unused regions or if the number of instances active in a region goes above a certain threshold.(Citation: CloudSploit - Unused AWS Regions)

Shield Active Defense

Behavioral Analytics

Deploy tools that detect unusual system or user behavior.

Instrument a system to collect detailed information about process execution and user activity, develop a sense of normal or expected behaviors, and alert on abnormal or unexpected activity. This can be accomplished either onboard the target system or by shipping data to a centralized analysis and alerting system.

Opportunity

There is an opportunity to detect the presence of an adversary by identifying and alerting on anomalous behaviors.

Use Case

A defender can detect adversaries leveraging unused cloud regions. By implementing behavioral analytics for cloud hosts interacting with the network from regions that are not normal, one can detect potential malicious activity.

Procedures

Use behavioral analytics to detect Living Off The Land Binaries (LOLBins) being used to download and execute a file. Use behavioral analytics to identify a system running development tools, but is not used by someone who does development. Use behavioral analytics to identify abnormal system processes being used to launch a different process.