T1525 - Implant Internal Image

Adversaries may implant cloud or container images with malicious code to establish persistence after gaining access to an environment. Amazon Web Services (AWS) Amazon Machine Images (AMIs), Google Cloud Platform (GCP) Images, and Azure Images as well as popular container runtimes such as Docker can be implanted or backdoored. Unlike Upload Malware, this technique focuses on adversaries implanting an image in a registry within a victim’s environment. Depending on how the infrastructure is provisioned, this could provide persistent access if the infrastructure provisioning tool is instructed to always use the latest image.(Citation: Rhino Labs Cloud Image Backdoor Technique Sept 2019)

A tool has been developed to facilitate planting backdoors in cloud container images.(Citation: Rhino Labs Cloud Backdoor September 2019) If an adversary has access to a compromised AWS instance, and permissions to list the available container images, they may implant a backdoor such as a Web Shell.(Citation: Rhino Labs Cloud Image Backdoor Technique Sept 2019)

Atomic Tests:

Currently, no tests are available for this technique.

Detection

Monitor interactions with images and containers by users to identify ones that are added or modified anomalously.

In containerized environments, changes may be detectable by monitoring the Docker daemon logs or setting up and monitoring Kubernetes audit logs depending on registry configuration.

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 monitor user interactions with images and containers to identify ones that are added or altered anomalously.

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.