MITRE Releases 'Shield' Active Defense Framework

MITRE Corp. has released a new guide cataloging measures that organizations can take to actively engage with and counter intruders on their networks.

Like MITRE's widely used ATT&CK framework, which offers a comprehensive listing of attacker behavior, the federally funded organization's new Shield is a publicly availably knowledge base, this time of tactics and techniques for proactive defense.

The core focus is on informing security practitioners about adversary engagement — or interacting with cyber intruders and figuring out how to mount a more active defense against them, says Bill Hill, CISO at MITRE.

"When noninteractive defenses like patching, firewalls, IDSs, etc., fail or are completely circumvented, what can we learn and how can we improve?" he says. Adversary engagement is "learning about how our adversaries attack us, what tools they use, what they will do after they establish a beachhead on our systems, maybe even what they want from us."

MITRE's new Shield framework presents information in a matrix format, in similar fashion as ATT&CK. The matrix consists of eight columns, each one listing different tactics — such as detect, disrupt, contain, and collect — that security practitioners can use to defend against intruders on the network. The hyperlinked data in the rows or each of the cells describes the actual techniques that defenders can use to implement each of these tactics.

For instance, the techniques listed in the individual cells under the "detect" column include API monitoring, behavioral analytics, email manipulation, and the creation of decoy accounts, networks, and credentials. Similarly, MITRE's recommended techniques for containing an adversary include baselining systems, system isolation and hardware, and software manipulation. By clicking on each of the cells, security professionals can then get more information on each technique, including the use cases for them.

MITRE's new Shield active defense framework identifies the opportunities for learning that defenders have from actively taking on and engaging with intruders on the network. "We believe that adversary actions not only present challenges, they also present opportunities to the defender," Hill says. "We consider these opportunities to be instances where the defender can take 'active' defense measures in order to change the game."

For example, by creating a decoy account, an organization could entice an adversary to take some action that would reveal information about their tactics and tools. Similarly, by seeding a target system with decoy credentials — such as fake usernames, passwords, and browser tokens — defenders can get alerts when an adversary accesses a particular resource or uses a specific technique, according to MITRE.

MITRE has mapped the post-compromise adversary behavior contained in its ATT&CK framework to the relevant defensive techniques in Shield. So by clicking on a particular adversary behavior in ATT&CK, defenders can quickly pull up MITRE's recommended tactic and technique for dealing with that specific behavior.

"Consider the techniques in Shield as active defense building blocks," says Christina Fowler, chief cyber intelligence strategist at MITRE. Some of them are basic and approachable, while some others are more sophisticated. "Each building block can be used alone or added to other building blocks to achieve something more elaborate. Defenders can begin with the basics, and go as far as their desire and resources take them."

Fowler says the creation of the Shield framework was prompted by MITRE's positive experience using active defense techniques over the past 10 years. "Thinking that nothing works with practitioners like details learned through experience," Fowler says, "we've put Shield together to see if we can really get a conversation started about the benefit of active defense."