LoFP / legitimate email service automation may attach amazonsesfullaccess to a service account. validate the target iam entity against known email automation roles and ci/cd pipeline identities. because this is a new terms rule keyed on the calling identity, recurring attachments by the same automation will not re-alert within the 7-day history window; first-time attachments by administrators performing legitimate setup may still trigger and should be validated against change management records.

Techniques

• T1098
• T1608

Sample rules

AWS SES Full Access Policy Attached to IAM Entity by Unusual User

• source: elastic
• technicques:
  • T1098
  • T1608

Description

Detects the first occurrence in 7 days of an AWS identity attaching the managed policy AmazonSESFullAccess to an IAM user, role, or group. AmazonSESFullAccess grants unrestricted permission to send email, manage identities and templates, manage suppression lists, and access SES account-level settings. Granting this policy to an unexpected IAM entity, particularly a newly created user or a role not previously associated with email operations, is a documented technique used by threat actors to establish phishing infrastructure on compromised AWS accounts, enabling them to send email on behalf of the victim organization’s trusted sending domain. Using new terms on the calling identity suppresses recurring attachments by known email automation while surfacing identities performing this action for the first time.

Detection logic

data_stream.dataset: "aws.cloudtrail"
    and event.provider: "iam.amazonaws.com"
    and event.action: ("AttachUserPolicy" or "AttachRolePolicy" or "AttachGroupPolicy")
    and event.outcome: "success"
    and aws.cloudtrail.flattened.request_parameters.policyArn: "arn:aws:iam::aws:policy/AmazonSESFullAccess"