- The “3 Legged Model” or “single firewall” – where the DMZ segment(s) are connected via a dedicated interface (or interfaces) and a single firewall implements traffic control rules between all of the network segments (the firewall could be a traditional firewall simply enforcing interface to interface rules or a “next generation” firewall implementing virtualized “zones” or other logical object groupings)
- The “Layered Model” or “dual firewall”- where the DMZ segment(s) are connected between two sets of firewalls, like a sandwich
It’s been a couple of busy months since we posted parts one and two of this series, so I’ll recap briefly here. Part one talked about the failure of information security programs to protect private data and systems from compromise. It showed that despite tighter controls and better security applications, there are more data security compromises now than ever. This was the basis for suggesting an increased emphasis on incident detection, incident response and user education and awareness; the Big Three.
Part two in the series discussed information security incident detection and how difficult it is to implement effectively. It related the sad statistic that less than one out of five serious data breaches is detected by the organization affected, and that a disturbing number of breaches go undetected for months before finally being uncovered. Part two also touted a combination of well configured security tools coupled with human monitoring and analysis as one of the best solutions to the problem. In this installment, we’ll discuss the importance of accompanying incident detection with an effective, well-practiced incident response plan.
Say that an ongoing malware attack on your systems is detected, would your staff know just what to do to stop it in its tracks? If they don’t do everything quickly, correctly and in the right order, what could happen? I can think of a number of possibilities right off the bat. Perhaps all of your private customer information is compromised instead of just a portion of it. Maybe your customer facing systems will become inoperable instead of just running slow for a while. Possibly your company will face legal and regulatory sanctions instead of just having to clean up and reimage the system. Maybe evidence of the event is not collected and preserved correctly and the perpetrator can’t be sued or punished. Horrible consequences like these are the reason effective incident response is increasingly important in today’s dangerous computing environment.
Developing and implementing an incident response plan is very much like the fire drills that schools carry out or the lifeboat drills everyone has to go through as part of a holiday cruise. It is really just a way to prepare in case some adverse event occurs. It is deconstructing all the pieces-parts that make up security incidents and making sure you have a way to deal with each one of them.
When constructing your own incident response plan, it is wise to go about it systematically and to tailor it to your own organization and situation. First, consider the threats your business is menaced by. If you have been conducting risk assessments, those threats should already be listed for you. Then pick the threats that seem the most realistic and think about the types of information security incidents they could cause at your organization. These will be the events that you plan for.
Next, look over incident response plans that similar organizations employ and read the guidance that is readily available our there (just plug “information security incident response guidelines” into a web browser and see what you get – templates and implementation advice just jump off the page at you!). Once you have a good idea of what a proper incident response plan looks like, pick the parts that fit your situation best and start writing. This process produces the incident response policies needed for your plan.
After your policies are set, the next step I like to tackle is putting together the incident response team. These individuals are the ones that will have most of the responsibility for developing, updating and practicing the incident response procedures that are the meat of any incident response plan. Armed with the written policies that were developed, they should be an integral part of deciding who does what, when it gets done, where they will meet, how evidence is stored, etc. Typically, an incident response team is made up of management personnel, security personnel, IT personnel, representative business unit personnel, legal representatives and sometimes expert consultants (such as computer forensics specialists).
Once all the policies, personnel and procedures are in place, the next (and most overlooked part of the plan) is regular practice sessions. Just like the fire drills mentioned above, if you don’t actually practice the plan you have put together and learn from the results, it will never work right when you actually need it. In all my time doing this sort of work, I have never seen an incident response practice exercise that didn’t expose flaws in the plan. We recommend picking real-world scenarios when planning your practice exercises and surprising the team with the exercise just as they would be in an actual event.
In the fourth and final installment of this series, we will discuss user education and awareness – another vital component in recognizing and fighting data breaches and system security compromises.
Thanks to John Davis for this post.
Information security techniques certainly are improving. The SANS Top Twenty Critical Controls, for example, are constantly improving and are being adopted by more and more organizations. Also, security hardware devices and software applications are getting better at a steady rate. But the question we have to ask ourselves is: are these improvements outpacing or even keeping up with the competition? I think a strong argument can be made that the answer to that question is NO! Last year there were plenty of high profile data loss incidents such as the Target debacle. Over 800 million records were compromised that we know of, and who knows how many other unreported security breaches of various types occurred?
So how are we going to get on top of this situation? I think the starkly realistic answer to that question is that we aren’t going to get on top it. The problem is the age old dilemma of defense versus attack; attackers will always have the advantage over entrenched defenders. The attackers know where you are, what you have and how you defend it. All they have to do is figure out one way to get over, under or around your defenses and they are successful. We, on the other hand, don’t know who the attackers are, where they’re at or exactly how they will come at us. We have to figure out a way to stop them each and every time – a daunting task to say the least! Sure, we as defenders can turn the tables on the information thieves and go on the attack; that is one way we can actually win the fight. But I don’t think the current ethical and legal environment will allow that strategy to be broadly implemented.
Despite this gloomy prognosis, I don’t think we should just sit on our hands and keep going along as we have been. I think we should start looking at the situation more realistically and shift the focus of our efforts into strategies that have a real chance of improving the situation. And to me those security capabilities that are most likely to bear fruit are incident detection, incident response and user education and awareness; the Big Three. Over the next several months I intend to expand upon these ideas in a series of blog posts that will delve tactics and means, so stay tuned if this piques your interest!
Thanks to John Davis for writing this entry.
The Top 20 Critical Controls for Effective Cyber Defense have been around for half a decade now, and are constantly gaining more praise and acceptance among information security groups and government organizations across the globe. One of the main reasons for this is that all of these controls have been shown to stop or mitigate known, real-world attacks. Another reason for their success is that they are constantly being updated and adjusted to fit the changing threat picture as it emerges.
One of these recent updates is the delineation of the “First Five” from the other “Quick Wins” category of sub-controls included in the guidance (Quick Wins security controls are those that provide solid risk reduction without major procedural, architectural or technical changes to an environment, or that provide substantial and immediate risk reduction against very common attacks – in other words, these are the controls that give you the most bang for the buck). The First Five Quick Wins controls are those that have been shown to be the most effective means yet to stop the targeted intrusions that are doing the greatest damage to many organizations. They include:
- Application white listing: Application white listing technology only allows systems to run software applications that are included in the white list. This control prevents both external and internal attackers from implementing malicious and unwanted applications on the system. One caveat that should be kept in mind is that the organization must strictly control access to and modifications of the white list itself. New software applications should be approved by a change control committee and access/changes to the white list should be strictly monitored.
- Secure standard images: Organizations should employ secure standard images for configuring their systems. These standard images should utilize hardened versions of underlying operating systems and applications. It is important to keep in mind that these standard images need to be updated and validated on a regular basis in order to meet the changing threat picture.
- Automated patching tools and processes: Automated patching tools, along with appropriate policies and procedures, allow organizations to close vulnerabilities in their systems in a timely manner. The standard for this control is patching of both application and operating system software within 48 hours of release.
- Removal or replacement of outdated software applications: Many computer networks we test have outdated or legacy software applications present on the system. Dated software applications may have both known and previously undiscovered vulnerabilities associated with them, and are consequently very useful to cyber attackers. Organizations should have mechanisms in place to identify then remove or replace such vulnerable applications in a timely manner just as is done with the patching process above.
- Control of administrative privileges and accounts: One of the most useful mechanisms employed by cyber attackers is elevation of privileges. Attackers can turn simple compromise of one client machine to full domain compromise by this means, simply because administrative access is not well controlled. To thwart this, administrative access should be given to as few users as possible, and administrative privileged functions should be monitored for anomalous behavior. MSI also recommends that administrators use separate credentials for simple network access and administrative access to the system. In addition, multi-part authentication for administrative access should be considered. Attackers can’t do that much damage if they are limited to isolated client machines!
Certainly, the controls detailed above are not the only security controls that organizations should implement to protect their information assets. However, these are the controls that are currently being implemented first by the most security-aware and skilled organizations out there. Perhaps your organization can also benefit from the lessons they have learned.
Thanks to John Davis for writing this post.