Terraform Provider for Linode Debug Logs Vulnerable to Sensitive Information Exposure

Impact

The Terraform Provider for Linode versions prior to v3.9.0 logged sensitive information including some passwords, StackScript content, object storage data, and NodeBalancer TLS keys in debug logs without redaction.

Important: Provider debug logging is not enabled by default.
This issue is exposed when debug/provider logs are explicitly enabled (for example in local troubleshooting, CI/CD jobs, or centralized log collection). If enabled, sensitive values may be written to logs and then retained, shared, or exported beyond the original execution environment.

Specifically:

• Instance creation operations logged the full InstanceCreateOptions struct containing RootPass and StackScriptData
• Instance disk creation logged InstanceDiskCreateOptions containing RootPass and StackscriptData
• StackScript update operations logged the complete script content via StackscriptUpdateOptions.Script
• Image share group member creation logged tokens in ImageShareGroupAddMemberOptions.Token
• Object storage operations logged full PutObjectInput structures containing user data
• NodeBalancer config create and update operations logged NodeBalancerConfigCreateOptions and NodeBalancerConfigUpdateOptions containing the SSLKey (TLS private key)

An authenticated user with access to provider debug logs (through log aggregation systems, CI/CD pipelines, or debug output) would thus be able to extract these sensitive credentials.

Patches

Update to version v3.9.0 or later, which sanitizes debug logs by logging only non-sensitive metadata such as labels, regions, and resource IDs while redacting credentials, tokens, keys, scripts, and other sensitive content.

Workarounds and Mitigations

• Disable Terraform/provider debug logging or set it to WARN level or above
  • To disable the logging, you can unset TF_LOG_PROVIDER and TF_LOG environment variables
  • Or you can set them to WARN or ERROR levels to avoid sensitive information logged in INFO and DEBUG levels.
  • See Terraform docs for details: https://developer.hashicorp.com/terraform/internals/debugging
• Restrict access to existing and historical logs
• Purge/retention-trim logs that may contain sensitive values
• Rotate potentially exposed secrets/credentials, including:
  • Root passwords
  • Image share group tokens
  • TLS private keys/certificates used in NodeBalancer configs
  • StackScript content/secrets if embedded

Credits

This issue was reported to Terraform by Hasan Sheet via Akamai's HackerOne Bug Bounty program.

Resources

https://github.com/linode/terraform-provider-linode/releases/tag/v3.9.0 https://github.com/linode/terraform-provider-linode/pull/2269 https://github.com/linode/terraform-provider-linode/commit/43a925d826b999f0355de3dc7330c55f496824c0