Best Practices For Endpoint DLP: Part 2

By Rich

In Part 1 I talked about the definition of endpoint DLP, the business drivers, and how it integrates with full-suite solutions. Today (and over the next few days) we’re going to start digging into the technology itself.

Base Agent Functions

There is massive variation in the capabilities of different endpoint agents. Even for a single given function, there can be a dozen different approaches, all with varying degrees of success. Also, not all agents contain all features; in fact, most agents lack one or more major areas of functionality.

Agents include four generic layers/features:

  1. Content Discovery: Scanning of stored content for policy violations.
  2. File System Protection: Monitoring and enforcement of file operations as they occur (as opposed to discovery, which is scanning of content already written to media). Most often, this is used to prevent content from being written to portable media/USB. It’s also where tools hook in for automatic encryption or application of DRM rights.
  3. Network Protection: Monitoring and enforcement of network operations. Provides protection similar to gateway DLP when a system is off the corporate network. Since most systems treat printing and faxing as a form of network traffic, this is where most print/fax protection can be enforced (the rest comes from special print/fax hooks).
  4. GUI/Kernel Protection: A more generic category to cover data in use scenarios, such as cut/paste, application restrictions, and print screen.

Between these four categories we cover most of the day to day operations a user might perform that places content at risk. It hits our primary drivers from the last post- protecting data from portable storage, protecting systems off the corporate network, and supporting discovery on the endpoint. Most of the tools on the market start with file and (then) networking features before moving on to some of the more complex GUI/kernel functions.

Agent Content Awareness

Even if you have an endpoint with a quad-core processor and 8 GB of RAM, the odds are you don’t want to devote all of that horsepower to enforcing DLP.

Content analysis may be resource intensive, depending on the types of policies you are trying to enforce. Also, different agents have different enforcement capabilities which may or may not match up to their gateway counterparts. At a minimum, most endpoint tools support rules/regular expressions, some degree of partial document matching, and a whole lot of contextual analysis. Others support their entire repertoire of content analysis techniques, but you will likely have to tune policies to run on a more resource constrained endpoint.

Some tools rely on the central management server for aspects of content analysis, to offload agent overhead. Rather than performing all analysis locally, they will ship content back to the server, then act on any results. This obviously isn’t ideal, since those policies can’t be enforced when the endpoint is off the enterprise network, and it will suck up a fair bit of bandwidth. But it does allow enforcement of policies that are otherwise totally unrealistic on an endpoint, such as database fingerprinting of a large enterprise DB.

One emerging option is policies that adapt based on endpoint location. For example, when you’re on the enterprise network most policies are enforced at the gateway. Once you access the Internet outside the corporate walls, a different set of policies is enforced. For example, you might use database fingerprinting (exact database matching) of the customer DB at the gateway when the laptop is in the office or on a (non split tunneled) VPN, but drop to a rule/regex for Social Security Numbers (or account numbers) for mobile workers. Sure, you’ll get more false positives, but you’re still able to protect your sensitive information while meeting performance requirements.

Next up: more on the technology, followed by best practices for deployment and implementation.

No Related Posts

[...] our last post we discussed the core functions of an endpoint DLP tool. Today we’re going to talk more about agent deployment, management, policy creation, [...]

By Best Practices for Endpoint DLP: Part 3 | securosi on

[...] started this series with an overview of endpoint DLP, and then dug into endpoint agent technology. We closed out our discussion of the technology with agent deployment, management, policy creation, [...]

By Best Practices For Endpoint DLP: Part 4 on

If you like to leave comments, and aren’t a spammer, register for the site and email us at and we’ll turn off moderation for your account.