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.

Monday, September 09, 2019

The Ransomware Economy

There's no doubt about it...cybercrime, and especially ransomware, is an entire economy in and of itself.

Don't believe me?

Read through this ProPublica article, not just once, but a couple of times.  And take notes.  Then go back and read the notes.  Here's what I got from the article:
  1. Organizations are looking to insurance policies to defray the costs of incidents.  Rather than investing in prevention, detection, and response, they're accepting (to some degree) that these incidents are going to happen, and seeking to establish a means to minimize their financial risk.  Hence, insurance policies.
  2. A ransomware incident occurs, and the policy kicks in.  Depending upon how the policy was set up, and what it covers, the deductible may be much less than the ransom.  Financial risk minimized.
  3. Insurance providers are more interested in getting ransoms paid quickly; getting the encryption keys and recovering files minimizes down time, and therefore any additional costs incurred as a result of services not being available.  So, insurance providers want the ransom paid, in order to minimize their financial exposure.
  4. There's also an entire economy that's popped up around ransom payment brokers, organizations that act as intermediaries between victim organizations, insurance providers, and the bad guys.
But is that the end?  Is this just about encrypting data and getting paid to unlock it?  I wouldn't think so, and here's why.  One of the things I've always been curious about is, is there any data exfiltration going on prior to data encryption?  Are bad guys taking anything before encrypting files?  In most cases, it's hard to tell...I'm aware of ransomware cases where the bad guys are actually in the environment for weeks or even months before encrypting files, and the artifacts of data staging and exfiltration may be fleeting, at best, and nonexistent during the incident response.

Not long ago, a fellow responder shared that many of the ransomware cases he works include an element of data exfiltration.  A recent 60Minutes segment on ransomware includes a similar statement; if you watch until 9:50 in the segment, you'll see mention of the bad guy further extorting an organization by threatening to leak their "internal data".

Let's look at some of the reporting on ransomware, such as this The Conversation article. At one point in the article, we see the statement:

Ransomware usually spreads via phishing emails or links...

Perhaps "usually", yes, but not always.  The 60Minutes segment mentioned the Samsam ransomware; during the first half of 2016, these guys were seen using the publicly available JexBoss exploit to gain access to organizations through JBoss CMS servers.  At that time, the average time between initial access to the organization and deploying the ransomware was 4 months. In 2017, in some cases, they switched to Terminal Services servers, gaining access via easily-guessed passwords.  Yes, some ransomware (some Ryuk incidents, for example) incidents begin with a phishing email, and then branch off into deploying remote access tools, internal reconnaissance, possibly privilege escalation, networking mapping, and finally, deploying the ransomware.

Another quote from the article:

Offenders will do their homework before launching an attack, in order to create the most severe disruption they possibly can.

Yes, they will.  But what does this mean?  This means a couple of things; first, they decide who to target, and when.  Employees within companies have targets against which they're judged; sales reps, for example, usually hit crunch time at the end of a quarter.  So, what the bad guys will do is send something to a sales rep that looks legit, and it's something that they need to open.  Yes, they're targeting individuals.

What does this look like, you ask?  While not related to ransomware, but take a look at the Mia Ash story, and you'll see what targeting looks like.  Going after sales reps, or the finance department, legal counsel...all of these are targets within an organization, and very often the "lure" looks attractive enough to obviate phishing awareness training.  However, this is only the beginning.  In the Mia Ash story, the adversary developed a relationship with their targets, to the point where, when it came time to send a weaponized document for the target to open, the target had no doubt in their mind regarding the fact that they were dealing with "Mia".

Something that isn't stated in the media is that, for some ransomware cases, once an adversary gains initial access to an infrastructure, there are a number of actions that must take place in order for them to have such an impact as to make paying the ransom the obvious choice going forward.  They need to observe and orient to where they are, collect information about the infrastructure, make decisions (that's the easy part, they're often quite practiced at this), and then act.  This is Col Boyd's OODA loop.  In some cases, this can take weeks, and in others, months.  Unfortunately, one of the things missing from public reporting of ransomware incidents, in addition to the observed initial access method, is the time that the adversary is on target before deploying ransomware.  It's not an easy task to go into a completely new infrastructure and find those files and systems that, if unavailable, would bring the organization to a halt.

With visibility, these actions can be detected, and responded to in a timely manner.  When I say, "responded to", I mean determining the initial infection vector and following a containment and eradication plan early in the adversary's process.  Let's say that you detect a new account being created on a system, because you have the visibility to do so...which user account was used to create the new one?  How did that user account gain access to the system on which the command was run?  Follow the tracks back to the starting point, and determine how the adversary got on the system, and then search your infrastructure for other, similar artifacts. 

It all starts with visibility.  Don't address ransomware by trying to figure out if you should restore systems from backup or pay the ransom; instead, catch the adversary early in their process and stop them before they encrypt their first file.

A Brief History of DFIR Time, pt I

Whether we like it or not, we're all time travelers. We're all moving through time, caught in the flow. In the western world, we're moving left-to-right, going along with the flow of time, from point A to point B. 

Sometimes it's interesting to look back at where we've been, what we've been witness to, and to reflect on and appreciate it.  Here's an abridged version of my take...

As a kid, my parents purchased a Timex-Sinclair 1000 computer.  I started out by following instructions for writing programs and saving them to a cassette tape...or trying to, as the case may be.  This wasn't the most reliable means (although it was the only one) for saving programs, and sometimes things would get corrupted, and I'd have to start all over.  As I learned a little bit of coding, I'd try different things...I'd start with the basic (no pun intended) recipe, and then make small modifications to see what happened.

In the early '80s, I was programming BASIC on the Apple IIe during a summer course.  Later, my parents purchased an Epson QX-10, which my father used for word processing.  During my senior year in high school, I took AP Computer Science, which involved programming PASCAL on the TRS-80 systems at the school.  My folks found a copy of Turbo PASCAL, which meant I could easily compile my programs at home in minutes, rather than trying to schedule time to get access to one of the TRS-80 systems at school, and get in before lunch, because compilation took over half an hour for some programs.

When I went to college (circa '85) we had a BASIC programming course, and we were still using the TRS-80 systems.  There were some mainframe systems in the physics building, and while I didn't get a real introduction to networking, some of did have fun sending messages to each other using the "wall" command.

After I got commissioned and went on active duty, I really didn't have a great deal of contact with computers.  In the Marine Corps at that time, Communications was a separate MOS from Data Processing, and as such, officers (and enlisted) for the MOSs attended separate schools.  For officers, both school houses were located on Quantico, at the time.  After training, I found that there was a great deal of cross-training in the fleet; quite often, CommOs were sent to data processing courses by their units.  The Marine Corps later combined the MOSs, along with the school houses and the curricula.

In the mid-'90s, I had the opportunity to attend graduate school, and I really got much more involved with computers.  I showed up with a 486DX desktop system that I used at home, and one of the first things I did was add a hard drive.  At the time, that meant putting it in the right location on the ribbon cable, and setting the correct jumpers on the drive chassis.  I later saved up and purchased additional RAM, going from 4MB to 16MB.  Yes, with an "M".  I also began going beyond Windows for Workgroups 3.11, and expanding into OS/2 2.1, and then later, OS/2 3.0 Warp.  At the time, I was using a SLIP/PPP script to dial into a local ISP, and then connecting remotely to the school systems.

Interestingly enough, I found someone in my local community who was running a BBS based on Amiga systems, and got a look at his setup.  That was a big deal at the time, because the town I lived in was close to a LATA border, meaning that while I could dial a number that was physically located about 10 miles south of me for no extra charge, the closest AOL POP was two miles north, and therefore, a long distance charge.  Eventually an airline pilot who lived in the local community set up an ISP, and I used that to access the Internet.

At school, I was working on SparcStations, using the Netscape browser.  I was learning about UseNet, SunOS, *nix-based systems, etc., none of which had anything to do with the curriculum.  I was the student rep to the sysadmin council when SATAN was released.  During the course of my "studies", I learned a little bit of C and C++ coding, a lot of MatLab, and a good bit of Java, at a time before Java was 1.0 GA status.  I played around with a bunch of different things with Java...I wrote programs to query fingerd, wrote an email spoofing program, and I wrote some code that connected the chargen port to the echo port...that was fun!

When I first started at graduate school, I didn't know it at the time, but I spent about 4 months walking by Gary Kildall's office every day on my way out of the building.  His office was next to one of the main doors that led out to the quad, where I'd go sit to each lunch. I never met Gary, nor took one of his courses, and again, it wasn't until much later that I found out who he was, and the role he played (or depending on your perspective, didn't play...) in the history of computing.  In one of my courses, I learned about the Hamming distance, and later took a seminar from Dr. Hamming himself.

As part of my master's thesis, I set up a lab; it consisted of two Cisco 2514 routers that I cross-connected, and from which I ran two small networks.  One was 10BaseT, the other 10Base2, and both had one Windows NT 3.51 server and three Windows 95 workstations.  The entire set up was connected to the campus backbone via a 10Base5 "vampire tap".  To collect data for my thesis, I wrote an SNMP polling application in Java, and processed the data using various statistical techniques in MatLab.

While I was in graduate school, one of my favorite courses was a new class in neural networks.  Part of the reason I liked it was due to how it was structured; the first half of the course was some instruction and small projects to get out feet wet, but the projects were small enough to allow us to stretch a bit, as well.  In many of the courses available at the time, the labs were such that it took most, if not all of the week to get them done, so there was very little learning beyond just finishing the minimum requirements for the lab.  In this course (and a few others), a different approach was taken, one that allowed the students to engage, experiment, and learn.  The second half of the course was a project, which was really cool to work on.  As it turned out, several of the students used that course as the basis for their master's wrote a program that could discern 'dirty' images of six consecutive Cyrillic characters (i.e., something you'd seen in a satellite photo of Red Square, for example.)  Another student created a neural network to assist with sonar identification.

So, how does all this matter?  Well, 24+ years later, I can discern what's behind the terms "ML" and "AI" that we see with respect to cyber security products.  ;-)

My time in grad school was also when I started brushing up against "information security" in the world of computers.  During a C programming course, I finished my assigned labs and wanted to learn a bit more, so I downloaded a file called 'crack.c' to see what it did.  All I ever did was open it in an editor, but the senior sysadmin for the department got upset.  She even told me that I had "violated security policies".  When I asked her to see the policies, knowing that I had never signed such a policy, I learned that there really was no written "policy".  That was to change more than a year later when a new Admiral took over the school, but at the time, there was no written security policy that any students read or signed.

After I graduated, I spent 8 months processing out of the military, and during that time was assigned to the Marine detachment at the Defense Language Institute (DLI).  While there, one of the things I did was get the detachment's computer systems connected to the DLI campus area network (CAN), which was token ring.  Also during that time, the Commandant of the Marine Corps (Gen. Krulak) had stated that Marines were authorized to play "Marine DOOM"; the setup at the detachment was six Gateway systems connected via 10Base2, running IPX.  I was able to use what I had learned just down the street (literally) to help get the "network" up and running.