Sigma rule: AWS KMS Imported Key Material Usage

Rule

Title

AWS KMS Imported Key Material Usage

Status

experimental

Level

high

Author

toopricey

Date

2025-10-18

File

rules/cloud/aws/cloudtrail/aws_kms_import_key_material.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the import or deletion of key material in AWS KMS, which can be used as part of ransomware attacks. This activity is uncommon and provides a high certainty signal.

Log source

product

aws

service

cloudtrail

Detection

selection:
    eventSource: 'kms.amazonaws.com'
    eventName:
        - 'ImportKeyMaterial'
        - 'DeleteImportedKeyMaterial'
condition: selection

False positives (as the rule lists them)

• Legitimate use cases for imported key material are rare, but may include, Organizations with hybrid cloud architectures that import external key material for compliance requirements.
• Development or testing environments that simulate external key management scenarios. Even in these cases, such activity is typically infrequent and should not add significant noise.

Tags

• attack.impact
• attack.t1486
• attack.resource-development
• attack.t1608.003

MITRE ATT&CK ids this rule names

• T1486
• T1608.003

References

• https://www.chrisfarris.com/post/effective-aws-ransomware/
• https://docs.aws.amazon.com/kms/latest/developerguide/ct-importkeymaterial.html
• https://docs.aws.amazon.com/kms/latest/developerguide/ct-deleteimportedkeymaterial.html

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/cloud/aws/cloudtrail/aws_kms_import_key_material.yml