Plunk is an open-source email platform built on top of AWS SES. Prior to 0.7.0, a Server-Side Request Forgery (SSRF) vulnerability existed in the SNS webhook handler. An unauthenticated attacker could send a crafted request that caused the server to make an arbitrary outbound HTTP GET request to any host accessible from the server. This vulnerability is fixed in 0.7.0.
Weakness
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.