request-url-http-3A-2F-2F169.254.169.254-2Flatest-2Fmeta data-2Fiam-2Fsecurity credentials-2F
: Because it is intended only for local use, the original version ( IMDSv1 ) does not require authentication; it assumes any request reaching it is legitimate because it came from the server itself. 2. How the Attack Works (SSRF)
The importance of this service from a security perspective cannot be overstated. While it is designed to be accessed only from within the EC2 instance, any vulnerable or malicious application running on that instance can also access it. This becomes a major liability when applications are susceptible to Server-Side Request Forgery (SSRF) attacks, as they can be tricked into making unauthorized requests on behalf of an attacker.
http://169.254.169.254/latest/meta-data/iam/security-credentials/ request-url-http-3A-2F-2F169
The impact depends entirely on the IAM role’s permissions. A role with AdministratorAccess means total compromise of the AWS account.
If the IAM role attached to the EC2 instance has extensive permissions (e.g., s3:* ), the attacker can steal data from S3 buckets, list instances, or move laterally within the network. 4. Securing the Metadata Service (IMDSv2)
Note: This exact technique was famously used in the massive Capital One data breach of 2019, resulting in the theft of over 100 million customer records. How to Secure Your Infrastructure While it is designed to be accessed only
The keyword utilizes standard URL encoding (percent-encoding) to pass special characters through web requests securely. 3A translates to : (colon) 2F translates to / (forward slash)
Historically, any process running on the server could query this IP to get information about the instance without providing a password or API key. Decoding the URL Pathway
The IP address 169.254.169.254 is a link-local address. In traditional networking, link-local addresses are used for autoconfiguration when no DHCP server is available. However, in major cloud environments like AWS, Google Cloud Platform (GCP), Azure, and DigitalOcean, this address is reserved for the . The Role of IMDS A role with AdministratorAccess means total compromise of
"Code": "Success", "Type": "AWS-HMAC", "AccessKeyId": "ASIA...", "SecretAccessKey": "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY", "Token": "FQoGZXIvYXdzE...[very long string]", "Expiration": "2025-12-15T00:00:00Z"
Always validate and sanitize any user-provided URLs or parameters that your application uses to make outbound requests. Use "allow-lists" rather than "deny-lists" to ensure the application only communicates with trusted domains. Implement the Principle of Least Privilege
What is IMDS? * What region and availability zone the instance/VM is running in. * What subnet the instance/VM is a part of. * The... SANS Institute Wiz x Cloud Security Championship: Perimeter Leak
Given the severity of the risks, a multi-layered defense strategy is essential to protect against IMDS-based attacks. The following are the most critical mitigations recommended by cloud security experts.
The vulnerable server blindly executes the request. Because the request originates from within the EC2 instance, AWS treats it as legitimate and returns the instance's temporary security credentials.