Denial of service vulnerability when parsing multipart request body

Summary

The request body parsing in starlite allows a potentially unauthenticated
attacker to consume a large amount of CPU time and RAM.

Details

The multipart body parser processes an unlimited number of file parts.
The multipart body parser processes an unlimited number of field parts.

Impact

This is a remote, potentially unauthenticated Denial of Service vulnerability.

This vulnerability affects applications with a request handler that accepts
a Body(media_type=RequestEncodingType.MULTI_PART).

The large amount of CPU time required for processing requests can block all
available worker processes and significantly delay or slow down the processing
of legitimate user requests.
The large amount of RAM accumulated while processing requests can lead to
Out-Of-Memory kills.
Complete DoS is achievable by sending many concurrent multipart requests in a
loop.