Data-2fiam-2fsecurity Credentials-2f — Callback-url-http-3a-2f-2f169.254.169.254-2flatest-2fmeta

: A parameter often used in web applications to tell a server where to send data after a task is finished.

The attacker uses these credentials to gain access to other AWS services (e.g., S3, RDS) using the AWS CLI or SDK. How to Prevent Metadata Exposure (IMDSv2)

The attacker then requests http://169.254.169 to get temporary credentials. What Can Be Stolen?

The 169.254.169.254/latest/meta-data/iam/security-credentials/ endpoint is a powerful convenience that becomes a major risk if not secured. As of 2026, the reliance on is non-negotiable for robust AWS security postures. Proper validation of "callback" URLs is the primary application-level defense against these critical breaches.

A special internal address accessible only from within an EC2 instance. /latest/meta-data/iam/security-credentials/ This directory lists the IAM roles attached to the server. : A parameter often used in web applications

In the world of cloud computing, metadata and security credentials play a crucial role in ensuring secure communication between services. Recently, a peculiar callback URL caught our attention: http://169.254.169.254/latest/meta-data/iam/security-credentials/ . In this feature, we'll embark on a journey to understand the significance of this URL and what it reveals about the inner workings of cloud infrastructure.

Seeing this pattern in application logs, web application firewall (WAF) alerts, or network traffic indicates that an attacker is actively attempting to exploit a Server-Side Request Forgery (SSRF) vulnerability. The ultimate goal is to steal identity and access management (IAM) role credentials and compromise the entire cloud environment. The Target: AWS Instance Metadata Service (IMDS)

In the original version (IMDSv1), the request was a simple HTTP GET request (as described above). IMDSv2 adds a mandatory session layer:

When you request this URL, the IMDS responds with the name of the IAM role attached to that instance. A subsequent request to a path containing that role name returns a JSON object with the holy trinity of cloud access: AccessKeyId , SecretAccessKey , and Token . An attacker possessing these three items can authenticate as the compromised EC2 instance and interact with the AWS API with that role's permissions. What Can Be Stolen

If the instance has a high-privilege role (e.g., AdministratorAccess), the attacker could take over the entire cloud environment. Recommended Remediation Steps

Let's produce the article. Understanding the Dangers of Metadata Service Callback URLs: A Deep Dive into http://169.254.169.254/latest/meta-data/iam/security-credentials/

When decoded, it points to the at the link-local IP address 169.254.169.254 . Accessing this specific path allows an attacker to extract temporary IAM security credentials directly from an EC2 instance, potentially leading to a full cloud account takeover. Anatomy of the Attack

Get the IAM Role credentials associated with the server. Proper validation of "callback" URLs is the primary

An attacker uses a Server-Side Request Forgery (SSRF) vulnerability to execute this attack. SSRF occurs when a backend server fetches data from a user-supplied URL without proper validation.

Once you have the role name, you query it directly to get the credentials: curl http://169.254.169

AWS introduced to mitigate SSRF. Unlike IMDSv1, v2 requires a session-oriented token, which is difficult to retrieve via simple SSRF. Ensure all EC2 instances are configured to deny IMDSv1 requests. 2. Restrict Network Access