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AWS IAM API Calls via Temporary Session Tokens

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AWS IAM API Calls via Temporary Session Tokens

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Detects sensitive AWS IAM API operations executed using temporary session credentials (access key IDs beginning with "ASIA"). Temporary credentials are commonly issued through sts:GetSessionToken, sts:AssumeRole, or AWS SSO logins and are meant for short-term use. It is unusual for legitimate users or automated processes to perform privileged IAM actions (e.g., creating users, updating policies, or enabling/disabling MFA) with session tokens. This behavior may indicate credential theft, session hijacking, or the abuse of a privileged role’s temporary credentials.

Rule type: new_terms

Rule indices:

  • filebeat-*
  • logs-aws.cloudtrail-*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Cloud
  • Data Source: AWS
  • Data Source: Amazon Web Services
  • Data Source: AWS CloudTrail
  • Data Source: AWS IAM
  • Data Source: AWS STS
  • Tactic: Persistence
  • Tactic: Privilege Escalation
  • Resources: Investigation Guide

Version: 4

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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Triage and analysis

Disclaimer: This investigation guide was created using generative AI technology and has been reviewed to improve its accuracy and relevance. While every effort has been made to ensure its quality, we recommend validating the content and adapting it to suit your specific environment and operational needs.

Investigating AWS IAM API Calls via Temporary Session Tokens

Temporary session credentials in AWS (identified by access keys beginning with "ASIA") are typically short-lived tokens issued by the AWS Security Token Service (STS). While they are legitimate and often used by developers or automation pipelines, their use in direct IAM management or privilege modification is highly unusual and may indicate credential misuse.

Attackers who compromise IAM users, roles, or federated identities can obtain session tokens to blend in with normal operations. They may then execute sensitive IAM API actions such as CreateAccessKey, PutUserPolicy, or UpdateAssumeRolePolicy to establish persistence, escalate privileges, or disable protections.

Possible investigation steps

  • Identify the actor
  • Review aws.cloudtrail.user_identity.arn and aws.cloudtrail.user_identity.type to determine the originating user or role.
  • Check event.original if ingested, look for sessionCredentialFromConsole: true. If this is present, the temporary session token was created as part of a legitimate console login session and this alert can be ignored.
  • Examine aws.cloudtrail.user_identity.session_context.mfa_authenticated — absence of MFA may indicate token misuse.
  • Analyze the API context
  • Review event.action and aws.cloudtrail.request_parameters for the exact IAM operation performed.
  • Identify whether the action modifies roles, user policies, trust relationships, or credentials.
  • Determine if this session token was associated with prior sts:GetSessionToken, sts:AssumeRole, or AWS SSO events.
  • Evaluate source and behavior
  • Inspect source.ip and user_agent.original for unexpected origins or tools.
  • Check if the request came from known infrastructure (e.g., CI/CD nodes, bastion hosts) or an anomalous network.
  • Compare @timestamp against normal operating hours or deployment schedules.
  • Correlate related activity
  • Look for subsequent or preceding activity using the same access key:
  • IAM changes (CreateUser, AttachUserPolicy, EnableMFADevice)
  • STS operations (AssumeRole, GetCallerIdentity)
  • CloudTrail or GuardDuty configuration changes (possible defense evasion)
  • If applicable, search for multiple users exhibiting similar patterns, a sign of large-scale token misuse.

False positive analysis

  • Expected automation
  • Some CI/CD pipelines, monitoring tools, or AWS SDK-based automation may perform IAM operations using temporary credentials.
  • Validate whether the IAM user or assumed role performing these actions belongs to an authorized automation workflow.
  • Administrative operations
  • Security or DevOps engineers may temporarily use session credentials for maintenance or testing.
  • Cross-reference with recent change tickets or known operations schedules.
  • Federated identity scenarios
  • Federated logins (via AWS SSO or external IdPs) can also generate temporary "ASIA" credentials. Verify if the source identity aligns with expected roles or groups.
  • Console Login Session
  • Console login sessions result in temporary "ASIA" credentials and can typically be ignored for this alert. This can be verified in event.original as sessionCredentialFromConsole: true

Response and remediation

  • Containment
  • If activity is unauthorized, immediately revoke the temporary session by invalidating the associated IAM credentials.
  • Rotate long-term credentials (access keys, passwords) for the parent IAM user or role.
  • Investigation
  • Search for all actions linked to the same access_key_id to assess potential persistence or lateral movement.
  • Examine the creation of new users, keys, or policies during or shortly after the detected session.
  • Recovery and hardening
  • Require MFA for all privileged actions using aws:MultiFactorAuthPresent conditions.
  • Implement detection coverage for follow-on persistence actions such as:
  • iam:CreateAccessKey
  • iam:PutUserPolicy
  • iam:UpdateAssumeRolePolicy
  • Educate administrative users and developers on secure token handling and the risks of shared credential reuse.

Additional information

For more information on detecting and mitigating session token abuse: - AWS Security Token Service (STS) Documentation - AWS IR Playbooks - AWS Customer Playbook Framework - Security Best Practices: AWS Knowledge Center – Security Best Practices.

Rule query

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event.dataset: aws.cloudtrail
    and event.provider: ("iam.amazonaws.com")
    and event.outcome: "success"
    and aws.cloudtrail.user_identity.type: "IAMUser"
    and aws.cloudtrail.user_identity.access_key_id: ASIA*
    and source.ip: *
    and not user_agent.original : "AWS Internal"

Framework: MITRE ATT&CKTM

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