Data Loss Prevention (DLP) is all the rage in this era of data security breaches and increasingly clever malware attacks. Naturally, every vendor in the security market wants a piece of the action.

But in the vendor stampede for market share, something disturbing is happening: Companies are buying technology that, once installed, doesn't offer all the ingredients of true DLP, according to Rich Mogull, former Gartner analyst and founder of security consultancy Securosis.

"The term DLP has essentially become meaningless because of a variety of vendors who wanted to say they were offering it," said Mogull, a respected voice in the industry [see Rich Mogull: 7 Infosec Trends for 2009].

The true definition of DLP has always been somewhat muddy. Mogull described the acronym as a buzzword created for marketing purposes. But it used to be easier to tell when a company was truly offering it. Mogull's definition of DLP goes something like this: "products that as a minimum identify, monitor and protect data in motion, at rest and in use through deep content analysis." The tool identifies the content, monitors its usage and builds defenses around it.

There are a ton of vendors who perform some of these functions. But unless they tackle everything in the above definition, Mogull said it's not truly DLP.

"Encryption and endpoint control vendors call what they do DLP," he said. "A firewall does some of what the concept entails. All of these tools are helpful in different areas of security, but they are not DLP."

Of course, when a vendor doesn't offer technology that purely tackles what everyone is clamoring for, a common solution is to buy up a vendor who has what they need and bake it into the product line.

Symantec muscled its way into the DLP space by acquiring Vontu, a company Mogull sees as an early leader of true DLP technology. Meanwhile, RSA snatched up Tablus (now part of the RSA Data Loss Prevention Suite) and McAfee bought Reconnex (see Data Security Tools to Not Overlook). Then there was the Websense acquisition of PortAuthority Technologies and CA's acquisition of Orchestria.

There are still a few independent DLP vendors out there, Mogull said, including Vericept and Code Green Networks.

Then there are the vendors who offer important pieces of the DLP puzzle but don't do everything necessary (under Mogull's definition, at least) to call themselves DLP providers.

"Many are helpful in their own way, including the portable device control vendors, the USB blockers, and so on," he said. "But they don't analyze content so they are not technically DLP."

Of course, like any technology, the perception of what is truly DLP depends on who you ask.

Imran Minhas, information security officer at the National Bank of Kuwait, said in his personal opinion DLP means prevention of confidential, restricted or internal-use data being leaked. User access to public/personal e-mail such as Hotmail and Yahoo are major concerns in this area.

"I haven't seen every single product out there but so far Symantec seems to be the best for DLP, mainly because of the ease of use," Minhas said.

Wayne Proctor, CISO at First Data USA, said the major trend he has observed in the DLP marketplace is for the vendors to extend from monitoring content only in outgoing traffic to monitoring other sources of data (primarily data at rest and data on endpoints).

"I don't view this as twisting the meaning of DLP but just leveraging their content evaluation engines to offer additional services," he said.

Proctor added that some of the DLP vendors offer services that are not leakage related, such as identifying potential disgruntled employees and persons who are downloading software that is not approved for usage on a company network.

"These types of additional services are certainly beyond the core focus of DLP but these are also value-added services that are fine to offer as long as the performance and effectiveness of the core DLP offerings are not negatively impacted," he said.

So how can an IT security practitioner avoid confusion when exploring DLP options? Mogull offers this parting advice:

"I don't care what someone calls what they are putting in front of me. Words can mean almost anything. I force the vendor to tell me in specific terms how their product does what it does. You say it prevents data loss? Great. Tell me exactly how. Oh, you encrypt. Oh, you monitor incoming content. Great."

The problem, he said, is that vendors often don't want the customer to know exactly how the product works. Therefore, it's the customer's responsibility to ask the probing questions.