Friday, September 20, 2019

A Brief History of DFIR Time, pt II

Continuing on from my previous post...

Once I left active duty, one of my first jobs was in an information security role, and I was doing a fair bit of "war dialing", which was fun. The main programs we used at the time were THC Scan and Tone Loc, but in a pinch, you could use the Windows dialer to connect to a number, and listen to the laptop speaker to determine what was on the other end.  In most instances, you'd get someone saying, "hello?", but in the few instances where a computer or fax would pick up, we'd note that and move on.  The laptops available at the time had built-in modems, as well as PCMCIA slots if you wanted to insert a network (ethernet or, yes, token ring) card.  Our laptop bags had phone and ethernet cables, but most companies wouldn't spring for a token ring card because (a) they were expensive and (b) not many customers had token ring networks.  Until you went on-site and someone said, "uh...oh, yeah...we use token ring." Of course, no one would say anything during the initial call unless you specifically asked, so that question went on script.

At that time, "computer forensics" was really not well known outside of very small circles, so there weren't much in the way of "go bags" or kits.  The few folks "doing" computer forensics at the time (that I was aware of) were largely former AF OSI enlisted folks, sequestered behind heavy duty doors with special locks.  When you did get a peek inside their wizardy world, the biggest component was a custom-built tower system with extra bays, and everything running on Linux.

At one point early in my career, I worked for a company that was trying to get into the security business, and while I was waiting for a contract, I taught myself Perl because that's a skill that the network engineering folks were looking for in candidates at the time, and I wanted to help out.  I never did get a chance to do any really extensive work for them, and I later moved on to a different company, this time performing more extensive (than just war dialing) vulnerability assessments.  My boss at the time told me that I would need to run the commercial scanner (ISS's Internet Scanner) for "about 2 to 3 yrs" before I would really understand what it was doing; within 6 months of getting the job, I was writing a tool to replace the commercial product, due to the number of false "hits" we were getting, many due to misinterpretation of the data returned from the query.

For example, there was the AutoAdminLogon value in the Registry; if the commercial tool found the value name, it responded with "AutoAdminLogon value set", even if the data for the value was "0".  Further, it never checked for the DefaultUserName or DefaultPassword values.  In one instance, the commercial tool determined that 22 systems within a customer's infrastructure had the value 'set', while the customer knew that it was only 1 system for which the value was actually set, and the system would automatically log into the Administrator account upon system boot; the other 21 had the value name, but the data was "0", and there was no username or password in the Registry.  They had already found those 21 systems and disabled the functionality through the UI; had we provided the findings from the commercial tool in our report, we would have been remiss, and the customer would have been correct in questioning the rest of the report.

Looking back, I realize that what I'd written was a "threat hunting" tool.  We didn't have any software at the time that could perform EDR functions; "visibility" consisted of either sitting at the console and opening Task Manager, or having the admin send a screen capture of Task Manager.  However, this tool was accessing systems and getting all sorts of data from it, including things like active modems, running services, applications, etc.  So while the tool wasn't able to monitor processes and network connections over time, it was able get point-in-time data, as well as look at what had occurred in the past on the system.  This was the '98-'99 time frame, and as such, a bit before terms like "adversary" and "APT" started to appear in our everyday usage.

I haven't always been in a consulting role.  At one point in my career, I took a position as a computer security engineer in an FTE role.  During that time, I responded to a couple of internal incidents, and wrote another "threat hunting" tool, albeit on a very limited scale.  The tool would access the Windows domain and get a list of all currently running systems; from there, it would access each system and collect the contents of several persistence locations.  When I first ran the tool, I'd get a LOT of data back, but over time and with no small amount of investigation, I developed a whitelist of authorized entries.  So, after a couple of weeks, I could launch the tool when I headed to a meeting or to lunch, and come back to a list of entries about half a page long.  This allowed me to see some issues, sometimes before they became really big issues, as well as identify trends across the infrastructure.  For example, there was one system that, because of it's location and the fact that it was used by overnight staff, kept popping up with "issues", no matter how many times I cleaned it.

Right around the '99-'00 time frame, I started attending and, more importantly, speaking at security conferences, including BlackHat and DefCon.  I had a great deal of experience with public speaking (I had been an instructor while I was on active duty, and classroom audiences were generally 250+ students...) but I was still a little nervous about presenting, because I had this image in my mind of what the audience was going to be like; today, we call this "imposter syndrome".  When I was an instructor in the military, I was a more experienced officer (albeit not by much...just a few years), speaking on my profession (i.e., communications). I was teaching new officers the basic skills they needed to learn, using the equipment I was very familiar with.  It was an entirely different environment, and here I was speaking to a roomful of people who, I figured, had a great deal more experience in the industry than I did.  And in some cases, that was a correct assumption, albeit not in all cases.  What I found when presenting on a solution I'd found to a problem I had was that there were others who had a similar problem, but had not yet arrived at a solution.  This realization really changed things for me, it really impacted my perspective, and it subsequently led to me submitting more and more.

For all of you out there who are thinking about submitting a presentation, and that thought scares you to death, ask yourself why that is.  More than likely, it's because you're thinking that you'll be judged.  And you're right, that's what people do.  However, the next time you're attending a speaking event, sit in the back of the room and just watch what everyone else is doing.  There will be lots of things they're doing...but one of them won't be paying attention, not for many folks, anyway.  Case in point, just a little over a month and a half ago, I gave a presentation, and at the beginning of the presentation, I stated...twice...when copies of the slides would be available.  The first question at the end of the presentation was...well, get three guesses, and the first two don't count.

My point is that a great deal of the anxiety that you feel when thinking about submitting to or just speaking at a conference is pretty normal, but it's also largely self-inflicted.  Don't let it paralyze you; instead, use it to fuel your development.  Use that energy to check the details of your presentation one more time, to rehearse one more time, to seek out feedback on the content one more time. 

And don't be afraid of people asking questions, because that fear will prevent you from actually listening to the question.  Remember, for all intents and purposes, you are the expert on the topic, and you're presenting your view, based on your perspective.  Yes, there are going to be other perspectives; don't be so overwhelmed by the fear of a question that you don't actually listen to the question.  I've been asked, "...did you look at...", as well as the more pointed, "...why didn't you consider...", and by listening to the question, I was able to get beyond that "imposter syndrome" anxiety and actually address the question.

One question I received back in the early 2000's was at an HTCIA International conference in Fairfax, VA...I was presenting on Registry analysis and someone in the audience, with a laptop in front of them, asked me, "what happens when you do X?"  I had a sudden flash of inspiration, and I turned the question around...I asked the person asking the question to try what he'd suggested, and tell us all what he found.  No, what he'd asked wasn't something I'd considered, but it did seem like a good rather than going back and forth on the specifics, I thought it would be a great idea to have them try it, in hopes of getting others to see that rather than going to someone else for answers, there are a great number of things we can try on our own, and discover for ourselves.

In 2005, Cory Altheide and I wrote the first published paper on tracking USB devices across Windows systems.  It's fascinating to look back and see not only how far we've come with this topic, particularly given how much the Windows operating system has changed over that time, but to also see how many times the paper is referenced. In most cases, the articles that reference our work are peer-reviewed articles, ones for which a literature search is a requirement.  Even so, it's pretty cool to see how many times that article is referenced.  Yes, there are a lot of those in the industry (as with any other industry) who "do" research without first performing a literature search, but that search is a pretty hard-and-fast requirement for academic, peer-reviewed papers, and it is pretty fascinating to see the number of references to our paper.

As digital forensics and incident response grew into something around which a service could be built and sold to customers, we started to develop "go kits", and there were lots of discussions and arguments on the Internet regarding what went into those kits.  Prior to the advent of enterprise-wide response capabilities (i.e., deploying an EDR monitoring tool, etc.), I had a Pelican case that weighed 65 lbs (I know because I had to check it in every time I flew out...), and contained two MacBook laptops, running Windows XP, two sets of hardware write-blockers, a wide assortment of cables, as well as hard copies of documentation.  I also had a laptop in my backpack with backup copies of all documentation, as well as hard copy of all pertinent phone numbers; if EVERYTHING failed, including my cell phone (notice I didn't say "smart phone", because we didn't have those at the time) battery, I still needed to be able to contact my boss, the customer, etc.  If I lost everything else, I could still get to a store, purchase a new laptop, put the tools I used on it (from a CD...remember those?), and get to work.

With the enterprise reach of EDR tools that we have at our disposal, there's a shift in how the DFIR industry reacts and provides services, but we still have a lot our original or age-old issues, due to the fact that as the industry has progressed, we've never really dealt with those issues.  Things like documentation and sharing of information or threat intel, specificity of language, correct data interpretation, not interpreting artifacts in isolation from other artifacts, etc.  These are things that we need to improve upon, as an industry.

Even so, it's been pretty fascinating to me to see how, in some cases, DFIR work has really progressed, particularly with respect to enterprise-wide response.  There's quick/timely deployment of visibility (i.e., EDR) from a remote location, data is collected and analyzed, and then answers are provided, very often before the next available flight to the location departs.  It's a brave new world out there regarding what can be done to respond to incidents.

No comments: