Conf42 DevSecOps 2023 - Online

Detect known unknowns

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Abstract

Project employed MITRE’s TTP-based hunting approach to develop detection analytics, tested on ad hoc machines to detect known unknowns, including reducing dwell time and single point of failure, and enhancing overall cyber defense posture.

Summary

  • A goal without a plan is just a wish. This can be applied to anything from your daily life to your work. In general, in order to exploited the full stratanting these needs to be backed up by an organized and sound strategy or plan.
  • Fulgio has a master's degree in computer science with a deeper dive in cybersecurity. He will explain why threatening should be more focused on ttps and hoc. And since he is italian, he will use a wine metaphor.
  • Pandora project aims to be proactive towards attacks, so proactive towards threat hunting, and not just passive. Will be placed between the infrastructure and the already present defensive system. Uses methodology developed and explained by Mitre.
  • As we know, every day new vulnerabilities are discovered. So you need to retweak what you have already done in the past and update it. And we could even go directly and tackle apts instead of ttps. This was all from me for today. I hope you like the talk.

Transcript

This transcript was autogenerated. To make changes, submit a PR.
You. Hi everyone, thank you again for joining in on my talk about practice, threat hunting and the impact that it can bring to your organization. So first of all, I wanted to bring forward this edition. A goal without a plan is just a wish. Of course this can be applied to anything from your daily life to your work, but it is also true for threatening in particular. The latter is a subject that has become very important if not fundamental for all those organizations that want to invest on a defensive infrastructure. But in general, in order to exploited the full stratanting these needs to be backed up by an organized and sound strategy or plan. So first of all, I wanted to represent myself. I'm Fulgio, I'm 25, I have a master's degree in computer science with a deeper dive in cybersecurity. I've been working for the past year and a half as an analyst and I'm currently head of the threat hunting project on an international client and I will talk about this later. So the pyramid that I was hinting before inside of the title slide is the famous or infamous pyramid of pain, developed by David Bianco. Well scores the amount of pain that specific indicators or iocs can bring to adversaries and attackers if the blue team or defensive team has had time and care to protect against them. So we go from the simplest ashbalus and eps to the more intricate ttps that are techniques, tactics and procedures. Of course, these are the ones that need more time and are more complex to take care of, especially on the detection field. However, these are the ones that can bring more value and more impact to the organization. And so in this talk we will see, I will explain or at least show why threatening should be more focused on ttps and hoc. This can be achieved, of course you could say, but why is it worth it? Is it necessary? And since I am italian, I will do a wine metaphor. So we can say that threat funding by itself is a nice bottle of wine, but with just little more we could buy a better, more tasteful wine that can increase our experience. But of course with a little bit more we can even reach for a charcuterie bore of cheese. And the cheese of course can go well with some orange gem. But overall these are all stuff that do not increase a lot the amount of money in our metaphor. So the effort needed to increase and have a better wine experience in this case. But in the thread in the cybersecurityanalyst field, a greater impact, greater achievements. So my colleague Nico that was incapable sadly today of joining us and I have been tackling the problem and endeavor of threat hunting based on ttps through the project that we have been bringing forward for the past one year, approximately, that is the Pandora project. The Pandora project starts from three main points. The first one is a single point of failure. So we wanted to avoid basing our detection solely on one defensive system. So in this case, we took both EDR and CM of the client as main points, as main defensive systems. And we applied so redundance. We wanted to focus on the reduction of the dual time, so of the adversary inside of the organization, basing our activity on assume the breach focus points. So we wanted to be proactive towards attacks, so proactive towards threat hunting, and not just passive. So not only after that the incident happened. And so we wanted to already complement before time the defensive services and the defensive system already put in place by the client. So where does this Pandora project present itself and position itself. So we have the attackers whose attacks, or at least the majority, are already blocked by these well defined services that are present commercially. So we have EDR, CM, AB and so on. But of course, as we know, especially nowadays, there have been a lot of techniques capable of circumventing such defensive measure. And so we want to go and block such activities, such possible aviation of the defenses. And so, as the picture explains, we will be placed between the infrastructure and the already present defensive system. But what kind of methodologies, what approach did we use towards threat hunting? In particular, we decided to shift from a simplistic, we could say model based solely on simple IOC. So the base of the pyramid of pain, where we find ashes and ips, since they are very brittle, meaning that an attacker can change them very easily and very quickly. And this is done currently to focus on ttps that we said are techniques, tactics and procedures that are more general, much more complicated and especially are more advantageous, since the attacker needs to change totally the approach to the attack. If we are able to defend against their kill chain, at least the kill chain that is being observed. And to do so, we applied the methodology developed and explained by Mitre, where the main graphic admission on the right, but that I decided to rewrite in order to demonstrate what we actually did and to better explain it. So we have first of all the first phase where we need inevitably to analyze and create a threat model, in this case of our client, but in general of what we want to defend. Because first of all, of course, virtually any kind of attacker can reach any kind of device of company and whatsoever. But we know that epts and in general attackers have preferences are more defined or specific towards sectors or towards specific kind of technologies. So the first important aspect is to understand what actually we want to defend from. This will help us also understand what kind of ttps actually we want to tackle. Because of course we could tackle them all, but these will be too much expensive. So we want first to focus on what is actually or has a much more higher probability of reaching us. After this, we take for example the first atp and understand actually what do we want to detect. So we study it, we create these abstract analytics and then we pass to the next phase that is determined data requirements, where we need to understand if we actually have visibility over this possible attack, this technique. So in this case, we need to understand if the data model is full. Otherwise, as the next case suggests, we need to understand what are the gaps and we need to as possible fill them. So we need to, for example, enable new event logs. We need for example to introduce new sensors or for example fix some misconfigurations, because possibly we already have such information, but we are losing them, so they are not tracked. And after this, we have one of the most important phases, that is the development first of all of the rules that of course can be defined accordingly according to the different languages that defensive services that are implemented have. But we also have the phase of the baselining that I will explain better, but that distinguishes such approach and also such project from the already put in use solutions. Then we have of course the testing phase where we take the queries. So the detection analytics that we have developed or that we want to develop to understand whether they actually work or not. Because of course theory is something, but practice is another. So in this case, we developed a specific virtual environment in order to replicate specific ttps. In this way, we both tested the base capabilities of the defensive services, but also the complementary detection capabilities that we introduce with our rules. And once we have tested all of this, of course we deploy the rules themselves and then we start the activity of hunting. Once, for example, the rule creates an alert. So, as I said, baselining is one of the fundamental aspects of this methodology, of this procedure, of this project. Also, because of course, services like commercially available EDRs and CMs already have put in place some rules that tackle a great quantity of TTPs. However, of course, voluntarily, they are not covering all of them. This is because they present themselves as general solution, not tailored like the one that we are presenting now. Because everything depends on the infrastructure of the organization itself, because every organization inside has a lot of events that create a lot of noise that inevitably either needs to be tuned by the organization itself. So I mean the vendor itself or by the analyst and the blue team of the organization. And this can of course become very expensive. In this case, we take this tool beforehand, so we see what are the possible events that can happen that can introduce noise, for example, daily routines introduced by GPO or activities by the operating system by itself. Or for example, we could have short lasting outliers, meaning the introduction of new technologies, of a new software, or fixing of something that introduces a lot of noise that we need actually to understand where it is coming from, who is doing it, in what is actually required by them. And of course, we have of course the classical noise introduced by admins and it people in general that can do all sort of activities that can mimic or can somewhat resemble some specific ttps, even though they are benign. So baselining is a fundamental part, especially in order to avoid disruption of daily operations due to the enormous number of potential false positives. In our case, then we have the threat model. That, as I said, is also a very important aspect. In our case, we took many different sources, for example, reports, and we didn't just stop like a couple of them or just one, because in order to have a complete picture, of course we need to understand the different studies that have been brought forward. Also to reduce the potential bias introduced by a vendor and its report. And the result, partially visible on the right, is a scale of what are the most used ttps inside of the threat model. And so at least an inspiration of what could be the first objectives to tackle. And then we have the testing environments that we have developed for such case. So we have produced three virtual machines. The first one is linked directly to the EDR. So it is an EDR agent in order to let us see what is the visibility of. For example, some mimicked attacks and techniques over this machine. For such reason they are called the detonation, since we detonate specific behavior. And instead we have another machine that is the CM one, that pretty much does the same exact thing of the EDR one, but with the CM agent. And then we have the lock collector that reaches those machines that are of course put in defensive net so that they do not spread malicious content all over the organization network, but that also functions as a log collector for possible analysis postmortem if we want to, for example, view the event logs. In particular, fundamental is that these machines, the detonation machine, at least mimic exactly the most common environment that is present inside of the organization of your organization. In this case the end user device that is one of the most device available to attackers that is most probably going to be infected eventually down the line. So the deliverables that then can be retrieved or are received after applying such methodology. And in our case so are many. So we have playbooks in the meaning that once of course you studied TTP and you master it, of course you know also what to check, how to circumvent it, what to actually observe, so you can create a simple guide for the analyst. But also, as we said, we have the mitigation of the gaps through for example network changes, security, new security event logs, new log sources and of course as previously we have a new testing environment put in place also for other possible activities like simple detonation of a malware. But we also have threat discoveries. For example, we could see anomalies already present inside of the organization, but of course we are developing them or these detection analytics also for future possible attacks to the organization. Now I will present a very simple case just to show what we actually did in our case. So we took two different techniques that share a common tool, in this case bitsadmin, and we are talking about ingress, tool transfer and persistent through system binding proxy execution. So we started by understanding what bitsubmin is developing, the abstract analytics. So what do we want to actually detect? What we would like to see in order to trigger an alert, we have the data dictionary, so what are the sources that can help us understand, for example, what in an endpoint can trigger us, can alert us. And we have either the event id for six, eight, eight. So the creation of a new process or the Seismon event id one. However, in our case the organization did not have or did not deploy Sisman and so we had in this case to work only with event id, but also in that case we had for example to fix the formatting or the parsing that was present inside of the CM in order for the queries to properly work. And so after such phases, as we said, we go directly to the creation of the rules, understanding what is the baseline, applying, so whitelisting. And then we have the testing phase. In testing phase, as we see, we used atomic red, that is a framework that presents itself perfectly for such activity, so it can replicate specific ttps and in our case we reproduce them. And as you can see in the following slide, the test demonstrate that actually neither EDR or CM were capable of detecting such subject activities, but instead with the application of the rules that we showed previously, but of course translated in the appropriate SQL language, query language were in fact capable of being detected. So as we can see here from this slide, we have actual results. So we have an alert of the EDR on the left, we have results on the query on the right, the query that will be introduced in the alert itself. And so we can see hoc. This approach actually incremented the visibility, incremented the efficiency and precision of the detection capabilities of the defensive system, of the organization itself. And so after such application, after, in this case, this rule, this scenario, what's next? What can be done? So, first of all, techniques are not set in stone. As we know, every day new vulnerabilities are discovered. So for example, it's possible that a technique that you have tackled has been updated. So you need to retweak what you have already done in the past and update it in order to be again efficient. Then after this we can of course go to the next TTP down the line in order to eventually and possibly finish the list that we have produced. And we could even go directly and tackle apts instead of ttps, apts meaning adversary and attackers meaning to tackle specifically their kill chain, their way of moving, even though I don't suggest following such behavior before having at least a mature enough model or defensive infrastructure behind. So this was all from me for today. I hope you like the talk, I hope you brought home something. And if you have any kind of question, you can always reach me at the contacts that I'm bringing you. And thanks again and have a nice conference.
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Fulvio Colombrino

Cyber Security Analyst @ Deloitte

Fulvio Colombrino's LinkedIn account



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