Added Binary Executed

This document describes a threat finding type in Security Command Center. Threat findings are generated by threat detectors when they detect a potential threat in your cloud resources. For a full list of available threat findings, see Threat findings index.

Overview

A binary that was not part of the original container image was executed. Attackers commonly install exploitation tooling and malware after the initial compromise. Ensuring that your containers are immutable is an important best practice. This is a low-severity finding, because your organization might not be following this best practice. There are corresponding Execution: Added Malicious Binary Executed findings when the hash of the binary is a known indicator of compromise (IoC).

Container Threat Detection is the source of this finding.

How to respond

To respond to this finding, do the following:

Step 1: Review finding details

  1. Open an Added Binary Executed finding as directed in Reviewing findings. The details panel for the finding opens to the Summary tab.

  2. On the Summary tab, review the information in the following sections:

    • What was detected, especially the following fields:
      • Program binary: the absolute path of the added binary.
      • Arguments: the arguments provided when invoking the added binary.
    • Affected resource, especially the following fields:
      • Resource full name: the full resource name of the cluster including the project number, location, and cluster name.
    • Related links, especially the following fields:
      • VirusTotal indicator: link to the VirusTotal analysis page.

  3. Click the JSON and note the following fields:

    • resource:
      • project_display_name: the name of the project that contains the cluster.
    • sourceProperties:
      • Pod_Namespace: the name of the Pod's Kubernetes namespace.
      • Pod_Name: the name of the GKE Pod.
      • Container_Name: the name of the affected container.
      • Container_Image_Uri: the name of the container image being deployed.
      • VM_Instance_Name: the name of the GKE node where the Pod executed.

  4. Identify other findings that occurred at a similar time for this container. Related findings might indicate that this activity was malicious, instead of a failure to follow best practices.

Step 2: Review cluster and node

  1. In the Google Cloud console, go to the Kubernetes clusters page.

    Go to Kubernetes clusters

  2. On the Google Cloud console toolbar, select the project listed in resource.project_display_name, if necessary.

  3. Select the cluster listed on the Resource full name row in the Summary tab of the finding details. Note any metadata about the cluster and its owner.

  4. Click the Nodes tab. Select the node listed in VM_Instance_Name.

  5. Click the Details tab and note the container.googleapis.com/instance_id annotation.

Step 3: Review Pod

  1. In the Google Cloud console, go to the Kubernetes Workloads page.

    Go to Kubernetes Workloads

  2. On the Google Cloud console toolbar, select the project listed in resource.project_display_name, if necessary.

  3. Filter on the cluster listed on the Resource full name row in the Summary tab of the finding details and the Pod namespace listed in Pod_Namespace, if necessary.

  4. Select the Pod listed in Pod_Name. Note any metadata about the Pod and its owner.

Step 4: Check logs

  1. In the Google Cloud console, go to Logs Explorer.

    Go to Logs Explorer

  2. On the Google Cloud console toolbar, select the project listed in resource.project_display_name, if necessary.

  3. Set Select time range to the period of interest.

  4. On the page that loads, do the following:

    1. Find Pod logs for Pod_Name by using the following filter:
      • resource.type="k8s_container"
      • resource.labels.project_id="resource.project_display_name"
      • resource.labels.location="location"
      • resource.labels.cluster_name="cluster_name"
      • resource.labels.namespace_name="Pod_Namespace"
      • resource.labels.pod_name="Pod_Name"
    2. Find cluster audit logs by using the following filter:
      • logName="projects/resource.project_display_name/logs/cloudaudit.googleapis.com%2Factivity"
      • resource.type="k8s_cluster"
      • resource.labels.project_id="resource.project_display_name"
      • resource.labels.location="location"
      • resource.labels.cluster_name="cluster_name"
      • Pod_Name
    3. Find GKE node console logs by using the following filter:
      • resource.type="gce_instance"
      • resource.labels.instance_id="instance_id"

Step 5: Investigate running container

If the container is still running, it might be possible to investigate the container environment directly.

  1. Go to the Google Cloud console.

    Open Google Cloud console

  2. On the Google Cloud console toolbar, select the project listed in resource.project_display_name, if necessary.

  3. Click Activate Cloud Shell

  4. Obtain GKE credentials for your cluster by running the following commands.

    For zonal clusters:

      gcloud container clusters get-credentials cluster_name --zone location --project project_name

    For regional clusters:

      gcloud container clusters get-credentials cluster_name --region location --project project_name

    Replace the following:

    • cluster_name: the cluster listed in resource.labels.cluster_name
    • location: the location listed in resource.labels.location
    • project_name: the project name listed in resource.project_display_name

  5. Retrieve the added binary by running:

      kubectl cp Pod_Namespace/Pod_Name:Process_Binary_Fullpath -c Container_Name  local_file

    Replace local_file with a local file path to store the added binary.

  6. Connect to the container environment by running:

      kubectl exec --namespace=Pod_Namespace -ti Pod_Name -c Container_Name -- /bin/sh

    This command requires the container to have a shell installed at /bin/sh.

Step 6: Research attack and response methods

  1. Review MITRE ATT&CK framework entries for this finding type: Ingress Tool Transfer, Native API.
  2. Check the SHA-256 hash value for the binary flagged as malicious on VirusTotal by clicking the link in VirusTotal indicator. VirusTotal is an Alphabet-owned service that provides context on potentially malicious files, URLs, domains, and IP addresses.
  3. To develop a response plan, combine your investigation results with the MITRE research and VirusTotal analysis.

Step 7: Implement your response

The following response plan might be appropriate for this finding, but might also impact operations. Carefully evaluate the information you gather in your investigation to determine the best way to resolve findings.

  • If the binary was intended to be included in the container, rebuild the container image with the binary included. This way, the container can be immutable.
  • Otherwise, contact the owner of the project with the compromised container.
  • Stop or delete the compromised container and replace it with a new container.

What's next