AWS STS

An Elastic detection rule identifies when a single AWS identity, using the AWS CLI, performs more than five distinct read-only discovery API calls (such as Describe*, List*, Get*, and Generate*) across various AWS services within a 10-second window, indicating reconnaissance by an adversary using compromised credentials or an exploited EC2 instance to map the AWS infrastructure for potential targets and further exploitation.

Adversaries leveraging compromised user credentials can perform a suspicious AWS STS AssumeRoot action by a rarely observed user and member account combination to escalate privileges and gain unauthorized access to AWS resources, potentially leading to data exfiltration or resource manipulation.

This threat detection rule identifies initial reconnaissance activities within AWS by flagging an IAM principal's first-time invocation of sensitive discovery APIs, such as GetCallerIdentity, ListUsers, ListBuckets, and DescribeInstances, when the originating IP address is associated with consumer VPNs, high-usage hosting providers, or networks linked to threat groups like TeamPCP, indicating an attacker performing enumeration of cloud resources from a suspicious network origin.

An Amazon Bedrock API key phantom user (IAM user starting with 'BedrockAPIKey-*') performing non-Bedrock API calls, such as to IAM, STS, EC2, VPC, or KMS, indicates credential misuse and realized privilege escalation by an attacker using added standard IAM access keys for reconnaissance or lateral movement beyond the intended Bedrock authentication boundary.

A low-privilege user with a freshly-provisioned SSO account in Netflix's Lemur certificate management service (versions <= 1.9.0) can exploit a Server-Side Request Forgery (SSRF) vulnerability in the ACME authority creation endpoint to reach the AWS EC2 Instance Metadata Service (IMDS), exfiltrating AWS STS credentials, and leveraging a creator-equality Insecure Direct Object Reference (IDOR) vulnerability for permanent access to PKI private keys, resulting in AWS IAM compromise and persistent certificate access.

This rule identifies suspicious SAML activity in AWS, such as AssumeRoleWithSAML and UpdateSAMLProvider events, which could indicate an attacker gaining backdoor access, escalating privileges, or establishing persistence.

Detection of AWS STS GetFederationToken calls with AdministratorAccess in the request parameters, indicating potential privilege escalation or dangerous automation via broadly privileged temporary credentials.

Abuse of AWS STS AssumeRole can allow attackers to move laterally within an AWS environment and escalate privileges, potentially leading to unauthorized access to sensitive resources and data.