Skip to content

Using Terrascan in command line mode

This section contains the following information:

The following is a description of all the commands available. Terrascan's interface is divided into subcommands as follows:

  • init = Initializes Terrascan by downloading the latest Rego policies into ~/.terrascan. The scan command will implicitly run this before a scan if it detects that there are no policies found.
  • scan = scans Infrastructure as code files based on the policies contained within the ".terrascan" directory
  • server = Starts the Terrascan's API server
  • help = You can view the usage menu by typing help or using the -h flag on any subcommand (e.g. terrascan init -h). You can also view this by typing terrascan without flags or other arguments.

Terrascan Commands

$ terrascan
Terrascan

Detect compliance and security violations across Infrastructure as Code to mitigate risk before provisioning cloud native infrastructure.
For more information, please visit https://docs.accurics.com

Usage:
  terrascan [command]

Available Commands:
  help        Provides usage info about any command
  init        Initialize Terrascan
  scan        Start scan to detect compliance and security violations across Infrastructure as Code.
  server      Run Terrascan as an API server
  version     Shows the Terrascan version you are currently using.

Flags:
  -c, --config-path string   config file path
  -h, --help                 help for terrascan
  -l, --log-level string     log level (debug, info, warn, error, panic, fatal) (default "info")
  -x, --log-type string      log output type (console, json) (default "console")
  -o, --output string        output type (human, json, yaml, xml) (default "human")

Use "terrascan [command] --help" for more information about a command.

Initializing (optional)

The initialization process downloads the latest policies from the repository into ~/.terrascan. By default the policies are installed here: ~/.terrascan/pkg/policies/opa/rego and are fetched while scanning an IaC. Use the following command to start the initialization process if you are updating the policies:

$ terrascan init

Note: The init command is implicitly executed if the scan command does not find policies while executing.

Scanning

If the scan command is used with no arguments (as shown below), the scan will include all supported cloud providers on Terraform HCL files:

$ terrascan scan

The scan command supports flags to configure the following: - Specify a directory to be scanned. - Specify a particular IaC file to be scanned. - Configure IaC provider type - Directory path to policies - Specify policy type.

The full list of flags for the scan command can be found by typing terrascan scan -h

Scanning current directory containing terraform files for AWS Resources

The following will scan the current directory containing Terraform HCL2 files for AWS resources:

$ terrascan scan -t aws

Scanning for a specific IaC provider

By default, Terrascan defaults to scanning Terraform HCL files. Use the -i flag to change the IaC provider. Here's an example of scanning kubernetes yaml files:

$ terrascan scan -i k8s

Scanning code remotely

Terrascan can be installed remotely to scan remote repositories or code resources using the -r and -u flags. Here's an example:

$ terrascan scan -t aws -r git -u git@github.com:accurics/KaiMonkey.git//terraform/aws

Important: The URLs for the remote repositories should follow similar naming conventions as the source argument for modules in Terraform. For more details, see this article.

Scanning private Terraform module repositories

When scanning Terraform code, Terrascan checks for the availability of the file ~/.terraformrc. This file contains credential information to authenticate a private terraform module registry. If this file is present, Terrascan will attempt to use the credentials when authenticating the private repository. For more details on the format of this file, please see Terraform's config file documentation.

Configuring the output format for a scan

By default Terrascan output is displayed in human friendly format. Use the -o flag to change this to YAML, JSON, XML, JUNIT-XML and SARIF formats.

Note: Terrascan exits with error code 3 if any issues are found during a scan.

Terrascan's output is a list of security violations present in the scanned IaC files. The example below is terrascan's out in YAML.

$ terrascan scan -t aws
results:
  violations:
  - rule_name: scanOnPushDisabled
    description: Unscanned images may contain vulnerabilities
    rule_id: AWS.ECR.DataSecurity.High.0578
    severity: MEDIUM
    category: Data Security
    resource_name: scanOnPushDisabled
    resource_type: aws_ecr_repository
    file: ecr.tf
    line: 1
  count:
    low: 0
    medium: 1
    high: 0
    total: 1

Scanning a Helm Chart

Helm chart can be scanned by specifying "helm" on the -i flag as follows:

$ terrascan scan -i helm

This command will recursively look for Chart.yaml files in the current directory and scans rendered .yaml, .yml, .tpl template files found under the corresponding /templates directory.

A specific directory to scan can be specified using the -d flag. The Helm IaC provider does not support scanning of individual files using the -f flag.

Scanning a Kustomize Chart

A Kustomize chart can be scanned by specifying "kustomize" on the -i flag as follows:

$ terrascan scan -i kustomize

This command looks for a kustomization.yaml file in the current directory and scans rendered .yaml or .yml template files.

A specific directory to scan can be specified using the -d flag. The Kustomize IaC provider does not support scanning of individual files using the -f flag.

Resource Config

While scanning a IaC, Terrascan loads all the IaC files, creates a list of resource configs and then processes this list to report violations. For debugging purposes, you can print this resource configs list as an output by using the --config-only flag to the terrascan scan command.

$  terrascan scan -t aws --config-only
aws_ecr_repository:
- id: aws_ecr_repository.scanOnPushDisabled
  name: scanOnPushDisabled
  source: ecr.tf
  line: 1
  type: aws_ecr_repository
  config:
    image_scanning_configuration:
    - scan_on_push:
        value: {}
    image_tag_mutability: MUTABLE
    name: test
- id: aws_ecr_repository.scanOnPushNoSet
  name: scanOnPushNoSet
  source: ecr.tf
  line: 10
  type: aws_ecr_repository
  config:
    image_tag_mutability: MUTABLE
    name: test

More details on scan command

List of options for scan command:

Flag Description Options (default highlighted )
-h Help for scan command See list of all flags supported with descriptions, default options in all commands are highlighted in bold
-d Use this to scan a specific directory. Use "." for current directory AWS, GCP, Azure, and GitHub
-f Use this command to scan a specific file
-i type Use this to change the IaC provider helm, k8s, kustomize, terraform
-i version Use this in conjuntion with - i type to specify the version of IaC provider Supported versions of each IaC are: helm: v3, k8s: v1, kustomize: v3, terraform: v12, v13, v14
-p Use this to specify directory path for policies By default policies are installed here:
-t Use this to specify individual cloud providers all, aws, azure, gcp, github, k8s
-r Use this to specify directory path for remote backend git, s3, gcs, http
-u Use this to specify directory URL for remote IaC repositories see options below
scan-rules Specify rules to scan, example: --scan-rules="ruleID1,ruleID2"
skip-rules Specify one or more rules to skip while scanning. Example: --skip-rules="ruleID1,ruleID2"
use-colours Configure the color for output (auto, t, f)
-v verbose Displays violations with all details
Global flags Description Options
-c Use this to specify config file settings Format supported is *.TOML
-l Use this to specify what log settings debug, info, warn, error, panic, fatal
-x Use this to specify the log file format console, json
-o Use this to specify the scan output type human, json, yaml, xml

Full help for scan command:

$ terrascan scan -h
Terrascan

Detect compliance and security violations across Infrastructure as Code to mitigate risk before provisioning cloud native infrastructure.

Usage:
  terrascan scan [flags]

Flags:
      --config-only               will output resource config (should only be used for debugging purposes)
  -h, --help                      help for scan
  -d, --iac-dir string            path to a directory containing one or more IaC files (default ".")
  -f, --iac-file string           path to a single IaC file
  -i, --iac-type string           iac type (helm, k8s, kustomize, terraform)
      --iac-version string        iac version (helm: v3, k8s: v1, kustomize: v3, terraform: v12, v13, v14)
  -p, --policy-path stringArray   policy path directory
  -t, --policy-type strings       policy type (all, aws, azure, gcp, github, k8s) (default [all])
  -r, --remote-type string        type of remote backend (git, s3, gcs, http)
  -u, --remote-url string         url pointing to remote IaC repository
      --scan-rules strings        one or more rules to scan (example: --scan-rules="ruleID1,ruleID2")
      --skip-rules strings        one or more rules to skip while scanning (example: --skip-rules="ruleID1,ruleID2")
      --use-colors string         color output (auto, t, f) (default "auto")
  -v, --verbose                   will show violations with details (applicable for default output)

Global Flags:
  -c, --config-path string   config file path
  -l, --log-level string     log level (debug, info, warn, error, panic, fatal) (default "info")
  -x, --log-type string      log output type (console, json) (default "console")
  -o, --output string        output type (human, json, yaml, xml) (default "human")