SSRF → cloud metadata → IAM credential theft
When it applies
You have SSRF and the app runs on a cloud VM/container with an attached role. The metadata endpoint hands out temporary credentials to anything that can reach it from the instance.
Why it works
IMDS lives at a link-local IP (169.254.169.254) and trusts network position, not identity.
SSRF gives you that position, so the app fetches the instance's role credentials for you —
then you use them against the cloud API with the app's permissions.
Method
- AWS IMDSv1 (no token): SSRF to
http://169.254.169.254/latest/meta-data/iam/security-credentials/→ role name →.../security-credentials/<role>returnsAccessKeyId,SecretAccessKey,Token. - AWS IMDSv2 (token required): needs a PUT to get a token, then a header on the GET —
possible only if the SSRF can set method +
X-aws-ec2-metadata-tokenheader. Many SSRFs can't; note IMDSv2 as the mitigation if it blocks you. - GCP:
http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/tokenwith headerMetadata-Flavor: Google(needs header-setting SSRF). - Azure:
http://169.254.169.254/metadata/identity/oauth2/token?...withMetadata: true. - Use the creds (in scope only): configure the CLI with the temp key/secret/token and run
read-only calls (
aws sts get-caller-identity,s3 ls) to prove impact — don't touch data.
Gotchas
- IMDSv2/
Metadataheader requirements defeat header-less SSRF — that's a finding (says v2 is on), not a dead end. - Temp creds expire fast; grab
sts get-caller-identityimmediately as proof. - Containers may hit the ECS task metadata (
169.254.170.2) instead of EC2 IMDS.
Verify success
aws sts get-caller-identity (or GCP/Azure equivalent) returns the instance role identity
using credentials pulled through the SSRF.
References
PortSwigger SSRF labs; AWS IMDSv2 docs; "SSRF to cloud takeover" write-ups.