I keep thinking about the
news reports that Chinese hackers managed to exfiltrate six terabytes
of sensitive data from a large number of systems belonging to the
Department of Homeland Security in November 2007. It seems like that
would be impossible to do without being detected. But, I have to
wonder, since the famous Richard Stiennon paper, Intrusion Detection is Dead,
organizations have been replacing IDS with IPS, and maybe, just maybe,
they think the devices do their job in some kind of "fire and forget"
mode. Sourcefire was kind enough to allow me to interview Snort creator and Sourcefire CEO Marty Roesch
on this topic, and we certainly thank him for his time.
Marty, do you
have a sense that detection is not a top priority these days, and do you
have any idea why?
Stephen, network monitoring seems to be out of vogue these days in
various corners of the security world for a variety of reasons.The litany of reasons seems to be unending
sometimes.Signature-based systemsaren't comprehensive enough.Evasion is an insurmountable problem.Wily hackers operate so stealthily that they're
impossible to detect. These criticisms of network monitoring are
not without merit but I believe that many of them don't understand the manner
in which network monitoring truly works today.
Well Marty, that is a cheery thought, what do you see as the primary attack vector these days?
So Marty, is the problem that these attacks are complex and, therefore, signatures are hard to write for systems like Snort?
Stephen, the pure signature-based methods that are so roundly
criticized by those "in the know" haven't been used for years as the
sole method ofunderstanding the assets and threats on networks.Understanding whatis on the network, what it is doing, how it is changing,
and who or what is interacting with it, are essential to understanding how to
defend today's networks properly. Today, the state of the art of network
monitoring doesn't rely on one technology or method to provide awareness.Network flow analysis, passive network
discovery, passive user discovery, stateful protocol analysis, attack mitigation,
packet logging andsignature-based mechanisms
can all be used in concert today to provide pervasive network awareness.
So, is it fair to
say that if you can define your network, and identify changes, that
might help you find attacks you would otherwise miss?
I strongly believe that networkawareness is really where we need to be headed with
monitoring technology and that seems to be the trend among the companies who
are continuing to work in the monitoring space.The ability to enumerate the assets in the environment, understand their
configuration, usage patterns and changes, as well as how that data correlates
to security events gives security practitioners the ability to see beyond the
meager and largely meaningless information that the Intrusion Detection Systems
of the 20th century provided.Done
properly, today's network monitoring infrastructure can run in a highly
automated fashion and only involve humans when necessary, cutting through the
noise and constant babysitting that plagued early generations of these
technologies.
I believe that network monitoring is a fundamental
capability required to have an effective security program.New technologies available during the last
few years have made it much more powerful and useful than it was even 3-5 years
ago, and I would recommend that all security practitioners take a good look at what is
available today.
Thanks Marty, I appreciate the insight. I would imagine your
company, Sourcefire, has some product or products that help you with
full-on network monitoring; can you give us the names of those tools
and any open source tools that you think are helpful as well?
Sourcefire offers the Sourcefire 3D System, a suite of technologies
to allow organizations to implement this next generation network
monitoring capability. Sourcefire RNA (Real-time Network
Awareness), RUA (Real-time User Awareness), and Snort products
implement all of the primary features I have mentioned. We bring a
holistic set of capabilities to organizations that need to monitor
large, sophisticated and disparate network environments in a way that
is manageable and scalable.
There are many open source tools that can send similar sets of data to
users who are willing to integrate the data into useful forms themselves. Technologies such as PADS, open source Snort, and
various NetFlow collection and visualization tools have been available
for several years and do provide a lot of the basic information that's
needed to do a more comprehensive job of monitoring network
environments against today's threats.
One last question, do yu have any suggestions for computer
security managers to find out how well their organization is doing at
detection, any actionable tips?
At the most basic level, managers need to
figure out what they've got and how it's changing; that's the
fundamental requirement for determining whether your detection is
working at all!
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