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

The IP address 169.254.169.254 is a used specifically by AWS to provide instance metadata to the machine itself. It is not accessible from the public internet. The Attack Vector: SSRF

A link-local address accessible only from within the virtual machine.

First, let’s decode the URL-encoded string: The IP address 169

To mitigate this, AWS introduced , which requires a session-oriented approach:

To counter this, cloud providers introduced IMDSv2. IMDSv2 requires a session-oriented defense mechanism consisting of two steps: First, let’s decode the URL-encoded string: To mitigate

Configure your WAF to inspect incoming request parameters for known SSRF attack strings. A robust WAF rule will flag and block any inbound traffic containing the encoded or decoded sequence of 169.254.169.254 . 4. Practice the Principle of Least Privilege

The presence of http-3A-2F-2F in the keyword indicates that someone is URL-encoding the colon and slashes to evade naive string matching. Web application firewalls (WAFs) and input filters often block http://169.254.169.254 but may miss variations such as: Anatomy of the Payload

Understanding how this exploit works, how the encoded callback URL triggers it, and how to properly migrate to IMDSv2 is crucial for securing cloud architectures. Anatomy of the Payload