Phishing is like spam in only one respect. They both come across email. In all other ways they're quite different.

People sending spam are trying to sell you something. People sending phishing attacks are trying to steal something from you. One type of communication is from a marketer -- whether legitimate or not. The other is from a thief. Further, spam is quite obviously spam, but phishing is getting increasingly difficult to detect. According to Word Spy, phishing is defined as: 'Creating a replica of an existing Web page to fool a user into submitting personal, financial, or password data.'

Despite what's at stake, many are ill prepared to deal with the increasing phishing threat. A common mistake that IT administrators make is to assume their spam solutions are equipped to handle phishing.

Though phishing comes through traditional email channels, it often bypasses gateways and spam filters by exploiting trusted domains and relationships. If you rely on authentication, a phisher who hijacks a trusted Web site can easily penetrate your system. If you operate with white lists and black lists, a hacker who has harvested those lists can send phishing attacks from a white list address. The Anti-Phishing Working Group (APWG) reports that more than 3,326 phishing sites were operating as of May 2005, with more than 107 trusted brands having been hijacked to perpetrate attacks.

''People feel that if they have a spam solution, they're protected from phishing, but that's not the case,'' says Jordan Ritter, CTO of Cloudmark, an anti-spam solutions company based in San Francisco. ''The nature of the problem, the attacks, and the form they take are incredibly different. Period. The way phishers operate and the way they send their mail is different, as well. There's no grey area there. They're stealing your money, assets, and information.

''For that reason, they have a lot more to lose, and move between systems quickly. They're a lot more sophisticated in taking advantage of security vulnerabilities, whereas spammers are trying to direct you to someone's Web site to buy something.''

It becomes an even more daunting threat when you consider that a majority of corporate IT and security administrators must defend more than one source of email.

Different Strategies

Companies that allow users to access their personal email through free email service providers must ensure that they've also added protective measures to that avenue of communication. The transient and seemingly invisible nature of phishing makes it a highly effective method of getting by generic spam solutions.

''Unlike spam, it's not something that you're going to be able to measure in terms of mail flow and volume and complaints,'' says Ritter. ''When you get stung with a phishing attack, you don't really know it. It's not an easy thing for the enterprise to measure. However, it's still a very real problem and when it relates to security, instead of simply mail administration, the corporation has a lot more to lose by not protecting its users. From that aspect, it's perhaps a greater liability for them.''

Clearly, traditional spam solutions aren't enough. Without obvious traces of the incidents, and the sophistication of the attacks increasing, what measures can a company take to effectively avoid becoming a victim?

''Anti-phishing is the newest area of Internet security,'' says the APWG's Dave Jevans. ''There are a number of companies providing innovative products and services in this area, but it's still a new and evolving science. Also, internal education can be an important factor. This is especially true when educating employees about avoiding internal phishing, i.e., attacks designed to spoof IT administrators and steal access credentials to internal systems.''

Over the past few years, it's been shown that layered security provides the highest form of defense in depth. The same is true when dealing with organizational phishing. Taking a proactive approach to bolstering the email infrastructure makes it much more difficult to find a way into your network.

The IT director of a popular Northern California Web services portal (who declined to be identified) provides a good example of having implemented this methodology.

''As a company, there are about four steps that we take,'' says the IT director. ''The first is corporate-wide user education to define phishing and what it looks like. The second thing we do is subscribe to some of the phishing notification newswires, and when we receive word of the latest phishing attacks, we'll assess them to see if we need to notify the entire staff. Third, we are actively evaluating several vendors' anti-phishing related plug-ins in the lab.

''Lastly, though it's really the front of the architecture, implementation of appropriate tools is critical,'' the IT director adds. ''While we have drawn a distinction between spam and phishing, one of our installed vendor products has the ability to catch them both. When I look at my personal email, outside of our network system, I see plenty of phishing. When I look at my mail inside our network, it's apparent that we do not get phished in the corporate system. We have indeed built a number of different layers behind that, but I can't remember the last time a phish got through our system.''

Approaching the threat from various avenues provides a more unified defense mechanism against a shape-shifting enemy. Through a combination of policy, process, education, and tools, it is possible to build a better fortress. Yet with every security challenge, there is no magic bullet.

Unfortunately for corporate America, there always will be so much out there for criminals to take advantage of.