AWS SSM Command Document Created by Rare User
Description
Identifies when an AWS Systems Manager (SSM) command document is created by a user or role who does not typically perform this action. Adversaries may create SSM command documents to execute commands on managed instances, potentially leading to unauthorized access, command and control, data exfiltration and more.
Query · kuery
data_stream.dataset: "aws.cloudtrail"
and event.provider: "ssm.amazonaws.com"
and event.action: "CreateDocument"
and event.outcome: "success"
and aws.cloudtrail.flattened.response_elements.documentDescription.documentType: "Command"
Investigation fields
Pivot points the source recommends for triage.
@timestampuser.nameuser_agent.originalsource.ipaws.cloudtrail.user_identity.arnaws.cloudtrail.user_identity.typeaws.cloudtrail.user_identity.access_key_idevent.actionevent.outcomecloud.account.idcloud.regionaws.cloudtrail.request_parametersaws.cloudtrail.response_elements
Known false positives
- Legitimate users may create SSM command documents for legitimate purposes. Ensure that the document is authorized and the user is known before taking action.
Analyst notes
Investigating AWS SSM Command Document Created by Rare User
This rule identifies when an AWS Systems Manager (SSM) command document is created by a user who does not typically perform this action. Creating SSM command documents can be a legitimate action but may also indicate malicious intent if done by an unusual or compromised user. Adversaries may leverage SSM documents to execute commands on managed instances, potentially leading to unauthorized access, command and control, or data exfiltration.
Possible Investigation Steps
- Identify the Actor: Review the
aws.cloudtrail.user_identity.arnfield to identify who created the SSM document. Verify if this user typically creates such documents and has the appropriate permissions. It may be unexpected for certain types of users, like assumed roles or federated users, to perform this action. - Analyze the Document Details:
- Document Name: Check the
aws.cloudtrail.request_parameters.namefield for the document name to understand its intended purpose. - Document Content: If possible, review
aws.cloudtrail.request_parameters.contentfor any sensitive or unexpected instructions (e.g., actions for data exfiltration or privilege escalation). If not available via logs, consider reviewing the document in the AWS Management Console. - Contextualize the Activity with Related Events: Look for other CloudTrail events involving the same user ARN or IP address (
source.ip). Examine actions performed in other AWS services, such as IAM, EC2, or S3, to identify if additional suspicious behavior exists. TheSendCommandAPI call may indicate attempts to execute the SSM document on managed instances. - Check Document Status and Metadata:
- Document Status: Confirm the document creation status in
aws.cloudtrail.response_elements.documentDescription.status. A status ofCreatingmay indicate that the document is in progress. - Execution Permissions: Review if the document specifies
platformTypesanddocumentVersioninaws.cloudtrail.response_elements.documentDescriptionto understand which environments may be impacted and if multiple versions exist.
False Positive Analysis
- Authorized Administrative Actions: Determine if this document creation aligns with scheduled administrative tasks or actions by authorized personnel.
- Historical User Actions: Compare this action against historical activities for the user to determine if they have a history of creating similar documents, which may indicate legitimate usage.
Response and Remediation
- Immediate Document Review and Deletion: If the document creation is deemed unauthorized, delete the document immediately and check for other similar documents created recently.
- Enhance Monitoring and Alerts: Configure additional monitoring for SSM document creation events, especially when associated with untrusted or rare users.
- Policy Update: Consider restricting SSM document creation permissions to specific, trusted roles or users to prevent unauthorized document creation.
- Incident Response: If the document is confirmed as part of malicious activity, treat this as a security incident. Follow incident response protocols, including containment, investigation, and remediation.
Additional Information
For further guidance on managing and securing AWS Systems Manager in your environment, refer to the AWS SSM documentation and AWS security best practices.