What is an “open” proxy?
Open proxies are proxies that have been accidentally, or purposefully, misconfigured to allow anyone to route internet traffic through them without proper safeguards. They serve as often-anonymous intermediaries, masking the original request endpoint from the target server. Open proxies are constantly abused for all manner of fraudulent activities: ddos attacks, spam, phishing attacks, brute-force cracking, etc. “Drone” machines are similar to open proxies, but may not be open or usable by the public at large. Instead, they are closed to all but a small group of individuals who have the necessary control priveleges. Drones are often created when a virus, spyware, or backdoor rootkit infects a target machine, and thereby allows external command and control. Large groups of open proxies and drones together form botnets. Both are identifiable by their fraudulent behavior, a sort of fraud fingerprint.
