A poorly written PHP script that includes files via user input (e.g., ?page=../../../../ etc.) can sometimes be manipulated to make HTTP wrappers fetch remote URLs if allow_url_include is enabled.
Inside that tree, one of the most sensitive branches is: /iam/security-credentials/ – which returns the temporary IAM role credentials attached to the instance. A poorly written PHP script that includes files
Understanding the AWS Metadata Security Risk: The Role of 169.254.169.254 The server then accidentally displays these credentials back
The IMDS responds to the server with the temporary IAM (Identity and Access Management) security credentials assigned to that server. The server then accidentally displays these credentials back to the attacker. Real-World Impact of IMDS Credential Theft Decodes payload and makes internal request to 169
[Attacker] │ 1. Submits encoded payload: "fetch-url-http-3A-2F-2F169.254.169.254..." ▼ [Vulnerable Web Server] │ 2. Decodes payload and makes internal request to 169.254.169.254 ▼ [AWS IMDS (v1)] │ 3. Returns IAM Temporary Access Keys ▼ [Vulnerable Web Server] │ 4. Reflects the AWS keys back in the HTTP response ▼ [Attacker] (Gains unauthorized AWS cloud access)
Here is a deep dive into what this URL means, why attackers target it, and how to defend your cloud environment against it. URL Decoding the Target
The attacker configures their local command-line interface (CLI) using the stolen Access Key ID, Secret Access Key, and Token.