: A command-line utility used to transfer data to or from a server using supported protocols (in this case, HTTP).
: IMDSv2 requires a PUT request to ensure that simple GET-based SSRF vulnerabilities cannot trigger a token generation.
curl http://169.254.169.254/latest/api/token
The IP address 169.254.169.254 is a link-local address used by cloud providers, most famously AWS, to distribute instance metadata. curl-url-http-3A-2F-2F169.254.169.254-2Flatest-2Fapi-2Ftoken
<?xml version="1.0" encoding="iso-8859-1"?> <!DOCTYPE html ...> <title>405 Method Not Allowed</title>
The string curl-url-http-3A-2F-2F169.254.169.254-2Flatest-2Fapi-2Ftoken represents a URL-encoded version of a critical command used in cloud computing. Specifically, it decodes to: curl http://169.254.169
This is the #1 threat vector. Imagine a web application that fetches a URL provided by a user (e.g., a profile picture fetcher). : A command-line utility used to transfer data
First, I need to assess the user's likely scenario. They are probably a developer, security professional, or tech writer. The deep need isn't just explaining curl and a URL. They likely want an educational or awareness piece about the risks of exposing or misusing this specific internal IP, common in cloud environments. The keyword's encoded form suggests it might appear in logs, URLs, or as part of a security scanning string (like for SSRF vulnerabilities). So the article should cover what this is, how it's used legitimately, and critically, the security implications like SSRF attacks, token leakage, and misconfigurations.
The ability to access and manipulate data via curl and the metadata service has several practical applications:
Understanding the IMDSv2 Token Request: curl url 169.254.169 First, I need to assess the user's likely scenario
Set --http-put-response-hop-limit 1 so that containers or proxies cannot forward metadata requests.
Prevent disaster before deployment. Scan your docker-compose.yml , serverless.yml , or application configs for strings resembling 169.254.169.254 . A common developer mistake is hardcoding curl tests into setup scripts and committing them to GitHub.