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Supply Chain Attack - Terraform

Description​

Terraform dependencies are not pinned, allowing a malicious actor to override the used components with malicious components without leaving a trace.

Impact​

Override depdendencies or component with malicious content.

Recommendation​

Use mechanisms such as git-commits, or artifacts and hashes to verify the data integrity.

Threat​

Anonymous attacker from Internet with write access to the provider releases.

Expected Remediation Time​

⌚ 15 minutes.

Score​

Default score using CVSS 3.1. It may change depending on the context of the vulnerability.

Base​

  • Attack vector: N
  • Attack complexity: H
  • Privileges required: N
  • User interaction: R
  • Scope: U
  • Confidentiality: N
  • Integrity: L
  • Availability: N

Temporal​

  • Exploit code madurity: U
  • Remediation level: O
  • Report confidence: R

Result​

  • Vector string: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N/E:U/RL:O/RC:R
  • Score:
    • Base: 3.1
    • Temporal: 2.6
  • Severity:
    • Base: Low
    • Temporal: Low

Code Examples​

Compliant code​

All terraform dependencies are pinned

required_providers {
  aws = {
    source  = "github.com/hashicorp/example"
    version = "3.23.0"
  }
}

Non compliant code​

There are unpinned terraform dependencies

required_providers {
  aws = {
    source  = "hashicorp/aws"
    version = "~> 3.23.0"
  }
}

Details​

Why​

Terraform providers are installed as:

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 3.23.0"
    }
    cloudflare = {
      source  = "cloudflare/cloudflare"
      version = "~> 2.20.0"
    }
  }

not only they are not pinned, but also a version like 2.20.0 has no guarantees because a malicious actor with access to the provider release process can override tags with malicious content, changing the legit 2.20.0 for malicious 2.20.0 without us noticing

Requirements​

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