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Curl-url-http-3a-2f-2f169.254.169.254-2flatest-2fapi-2ftoken May 2026

The specific URL you mentioned is the endpoint for retrieving a session token on AWS EC2 instances, a key part of IMDSv2 (Instance Metadata Service Version 2). This version was designed specifically to mitigate SSRF (Server-Side Request Forgery) vulnerabilities. The Story of IMDSv2

In 2019, Capital One suffered a massive data breach where an attacker exploited a SSRF vulnerability to access a server's metadata. In the older IMDSv1, a single GET request could yield sensitive IAM role credentials. AWS responded by introducing IMDSv2, which requires a "session-oriented" approach: Step 1: Use a PUT request to generate a temporary token.

Step 2: Use that token in the header of subsequent metadata requests. Interesting Blog Posts to Read

If you are looking for deep dives into how this works and why it matters, these posts are excellent resources:

AWS Security Blog: Add Defense in Depth with IMDSv2 – The official breakdown from AWS on why they moved away from the simple GET request and how the token-based system thwarts common SSRF attack vectors. curl-url-http-3A-2F-2F169.254.169.254-2Flatest-2Fapi-2Ftoken

Netflix Tech Blog: Lessons from IMDSv2 (Search for "IMDSv2") – Netflix is famous for its cloud security; they often document their migration strategies and how they enforce IMDSv2 across thousands of instances to eliminate the "old way" of accessing metadata.

Hacking the Cloud: AWS Instance Metadata – A community-driven encyclopedia that explains the transition from an attacker’s perspective, showing exactly how IMDSv2 stops classic exploitation techniques. Practical Command Example

To see it in action, you first grab the token (valid for 6 hours in this example) and then use it:

# Get the token TOKEN=`curl -X PUT "http://169.254.169" -H "X-aws-ec2-metadata-token-ttl-seconds: 21600"` # Use the token to get instance identity curl -H "X-aws-ec2-metadata-token: $TOKEN" http://169.254.169 Use code with caution. Copied to clipboard The specific URL you mentioned is the endpoint

http://169.254.169.254/latest/api/token

This URL is a special one used in cloud computing, particularly with Amazon Web Services (AWS) and possibly other cloud providers that support similar metadata services. Here's a breakdown of what it is and its usage:

What metadata can you get?

That last bullet point is why this IP address is sacred to attackers.

What Is This Endpoint?

169.254.169.254 is a special IP address used by cloud providers (AWS, GCP, Azure, etc.) to serve instance metadata. The specific path /latest/api/token is part of IMDSv2 (Instance Metadata Service Version 2), introduced by AWS to protect against SSRF (Server-Side Request Forgery) attacks.

Attack scenario 2: RCE (Remote Code Execution) payloads

Once an attacker has command execution on a VM (via a vulnerability like Log4Shell), they run: This URL is a special one used in

TOKEN=$(curl -X PUT "http://169.254.169.254/latest/api/token" -H "X-aws-ec2-metadata-token-ttl-seconds: 21600")
curl -H "X-aws-ec2-metadata-token: $TOKEN" http://169.254.169.254/latest/meta-data/iam/security-credentials/

Then they export the keys and assume the IAM role from their own machine.

Part 6: How to Protect Your Cloud Infrastructure Against Metadata Service Abuse

IMDSv1 (the old way)

You could request:

curl http://169.254.169.254/latest/meta-data/iam/security-credentials/some-role

And it would directly return IAM credentials in plaintext. No authentication, no token, no headers. Any process on the VM — including a compromised web application — could get admin keys.

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