Prevent Destroy Encryption

Adds prevent_destroy = true to KMS keys and Secrets Manager secrets. Blocks accidental deletion of encryption infrastructure.

Why this rule exists

Deleting a KMS key is irreversible after the waiting period (7-30 days). Any data encrypted with that key becomes permanently inaccessible: S3 objects, RDS snapshots, EBS volumes, everything. Deleting a Secrets Manager secret can break applications that depend on stored credentials, API keys, or configuration values.

Unlike data resources where backups might help, losing a KMS key means losing access to the data itself. There is no recovery path.

Related Terraform and OpenTofu issues

Limitations this rule answers

Per-module pages under Workarounds where this rule is the answer, each with the native workaround first and the diff the rule makes:

• KMS: terraform destroy scheduled deletion of a KMS key
• Secrets Manager: terraform destroy deleted a secret other systems depend on

Affected resources

What this rule does

Adds a lifecycle { prevent_destroy = true } block to each matching resource. Terraform and OpenTofu will refuse to destroy these resources during terraform destroy or resource replacement.

Before and after

Before (upstream module):

resource "aws_kms_key" "this" {
  # ... resource configuration ...

  tags = var.tags
}

After (with Prevent Destroy Encryption applied):

resource "aws_kms_key" "this" {
  # ... resource configuration ...

  tags = var.tags

  lifecycle {
    prevent_destroy = true
  }
}

The only change is the rule transformation. All existing arguments, outputs, and module behavior remain identical.

The example above is illustrative. To see this rule run for real, open it in the Rules Playground — it applies lifecycle_prevent_destroy_encryption to a reviewed upstream module that actually declares the resources this rule targets, and shows the diff the registry would serve. No account needed.

Known limits

• Does not cover aws_kms_alias, aws_kms_grant, or other KMS-related resources.
• Does not prevent KMS key disabling (only deletion). A disabled key can be re-enabled.
• Does not cover AWS Certificate Manager (ACM) certificates or other encryption-adjacent resources.
• For prevent_destroy, add means ensure this value, not add it if absent. A resource that explicitly declares prevent_destroy = false is rewritten to true; before pofix 0.21 it was left unprotected while the run still reported the rule as applied. A value that is not a true/false literal is left alone and warned about instead of being rewritten.
• Only .tf and .tofu files are read. Modules written in JSON syntax (.tf.json, .tofu.json) are left untouched.
• Only the module's own directory and its first-level modules/* submodules are processed. Modules that this module calls by source URL are separate downloads and are handled on their own request.

Compliance framework support

This rule is not a compliance control. It supports these framework objectives as an operational safeguard:

Default configuration

These are the values the rule ships with. They are not settable from a module source URL: ?rules= carries rule names only, so a per-request enable uses exactly the defaults below. Your organization sets them per rule, in its Baseline or in a ruleset, from the Operational Rules page; see Baseline rules and rulesets.

The rule's definition

The HCL this rule is written in - its parameters, their shipped defaults, and the transformers it runs - is published at lifecycle_prevent_destroy_encryption, alongside every other selectable rule.

How to enable

On a framework host, per request:

Add ?rules=lifecycle_prevent_destroy_encryption to your HTTPS module source, using the id exactly as written.

module "example" {
  source = "https://soc2.compliance.tf/terraform-aws-modules/s3-bucket/aws?version=5.0.0&rules=lifecycle_prevent_destroy_encryption"
}

A ?rules= list is either all bare names, which replace your organization's rules for that download, or all - prefixed names, which subtract from them. Mixing the two is refused with a 400 rather than silently treated as a replacement. To add this rule on top of your organization's rules instead, use ?add_rules=lifecycle_prevent_destroy_encryption; a bare ?rules= list cannot be combined with it, because a bare list already replaced the set there was something to add to.

The + add prefix was removed. It reached the registry only when written %2B, and a literal + in a query string decodes to a space everywhere, so ?rules=+lifecycle_prevent_destroy_encryption arrived as a bare name with a leading space — one step from silently replacing your organization's rules. Any +, in either spelling, is now a 400 naming ?add_rules=.

On your organization's host:

Add the rule to the organization's Baseline, which applies to every module served from the bare organization form <alias>.compliance.tf/<namespace>/<name>/<provider>, or to a named ruleset that one module selects with ?ruleset=<name> on the HTTPS form of that address. A project environment (<alias>.compliance.tf/<project>/<env>/<module>) serves the rules frozen in its bound snapshot instead: there the rule goes into the config draft and reaches the environment by promotion. On both organization forms ?rules= and ?add_rules= are refused with a 400 — including the subtractive - prefix — rather than dropped, so you cannot mistake an ignored override for an applied one. Change the configuration, not the URL. See Baseline rules and rulesets for the configuration flow, and registry resolution for how the address forms differ.

Break-glass path

On a framework host, add ?rules=-lifecycle_prevent_destroy_encryption to the module source URL and run terraform init -upgrade to fetch a copy without this rule. The copy in .terraform/modules/ stays until the next upgrade, so remove the override when you are done. On your organization's host the parameter is refused with a 400 rather than ignored. The rule comes from the organization's configuration: a Baseline rule applies to every module served from the bare organization form, so an admin disables it for the duration of the operation, or keeps it out of the Baseline and in a ruleset that only the modules needing protection select. On a project environment the posture is the bound snapshot and its waivers. See Baseline rules and rulesets.

Failure modes