Request-url-http-3a-2f-2f169.254.169.254-2flatest-2fmeta Data-2fiam-2fsecurity Credentials-2f New! [2024-2026]

aws s3 ls --profile stolen aws ec2 describe-instances --region us-east-1

If a server-side script executes shell commands that include user input, an attacker might inject:

"Code": "Success", "Type": "AWS-HMAC", "AccessKeyId": "ASIA...", "SecretAccessKey": "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY", "Token": "FQoGZXIvYXdzE...[very long string]", "Expiration": "2025-12-15T00:00:00Z" aws s3 ls --profile stolen aws ec2 describe-instances

Configure network firewalls to block outbound traffic from the application layer to 169.254.169.254 .

169.254.169.254 is a special reserved for metadata services. It is not reachable from the public internet — only from within the virtual network of the cloud provider or from the instance itself. Cure the underlying application flaw by validating all

Cure the underlying application flaw by validating all user-supplied URLs against a strict whitelist. Block any inputs containing: Literal IP addresses ( 169.254.169.254 , 127.0.0.1 ). Hexadecimal, octal, or URL-encoded variations of those IPs. DNS names that resolve to local loopback or private ranges. Apply the Principle of Least Privilege

The most common way attackers exploit this endpoint is through . Consider a web application that fetches images or data from user-supplied URLs. If the developer fails to validate or sanitize the input, an attacker can provide: DNS names that resolve to local loopback or private ranges

Web servers log incoming traffic or application inputs using specific encodings to handle special characters. decodes to a colon ( : ). 2F decodes to a forward slash ( / ).

Enable GuardDuty and CloudTrail to monitor for unusual API calls. Look for "UnauthorizedAccess:IAMUser/InstanceCredentialExfiltration" findings in GuardDuty, which specifically detect when EC2 credentials are used from an IP address outside of the AWS environment.