I have noticed a large amount of server-side HTTP client libraries accept untrusted TLS communication by default. For example, from the documentation for node's request:
strictSSL- If true, requires SSL certificates be valid.
false unless set, in other words, untrusted SSL certs are accepted by default. I'm not specifically picking on request, it's by no means alone when it comes to this behaviour.
What are obvious attack vectors for server-to-server communication (typically a REST API) using untrusted SSL certs?
Eg, DNS cache poisoning could be used to replace the real endpoint with an attacker's replacement that uses a self-signed cert.
Are there others?