Ruby: Resolv::getaddresses bug that can be abused to bypass security measures.

Description Resolv::getaddresses is OS-dependent, therefore by playing around with different IP formats one can return blank values. This bug can be abused to bypass exclusion lists often used to protect against SSRF. | 💻 Machine 1 | 💻 Machine 2 | |--------------|---------------| | ruby 2.3.3p222...