How Are Open Proxies a Security Risk?
The problem with open proxies is that anyone on the Internet can use them as go-betweens to perform just about any action related to Internet access. (To see how you’d configure proxy servers for a number of types of Internet traffic in Mac OS X, check out the Proxies tab in the Network preference pane.) The most frequent exploit of an open proxy is to bypass local content filtering – ironically, this exploit basically uses one proxy filter to bypass another. In the many open proxy logs I have examined, 95 percent of the hits fall into this category. Spammers seem to have discovered open proxies sometime in the last year, probably as the number of mail servers allowing open relaying started to drop dramatically. Some of the recent Windows/Outlook virus outbreaks were really just Trojan horses with hidden open proxy code as the true payload. Noisy, high-profile worms like Blaster kept everyone, including the media, distracted while the other worms managed to create, within the space of
