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

http://169.254.169.254/latest/api/token

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The use of 169.254.169.254 specifically is standardized across various cloud platforms for their instance metadata services. It works because this IP address is not routable and thus can only be accessed by the instance itself, providing a mechanism for the instance to learn about its environment. curl-url-http-3A-2F-2F169.254.169.254-2Flatest-2Fapi-2Ftoken

The command curl http://169.254.169 initiates a session-oriented request to the Amazon Web Services (AWS) Instance Metadata Service Version 2 (IMDSv2), serving as a crucial defense against Server-Side Request Forgery (SSRF) attacks. This method mandates a token-based, two-step authentication process, replacing the vulnerable IMDSv1 to secure EC2 instance metadata and IAM role credentials. http://169

URL-encoding (http-3A-2F-2F for http://) is a common obfuscation technique to evade pattern matching. Security tools must decode strings before comparing against known malicious patterns. Let me decode it for you: The use of 169

How IMDSv2 Works

  1. Token retrieval: The instance first makes a PUT request to http://169.254.169.254/latest/api/token with a X-aws-ec2-metadata-token-ttl-seconds header (e.g., 21600 for 6 hours).
  2. Token usage: The returned token is then included in subsequent metadata requests using the X-aws-ec2-metadata-token header.
  3. Metadata access: With the token, the instance can access paths like /latest/meta-data/iam/security-credentials/role-name.