Wednesday, March 20, 2019

Recovering Luddite?

Growing up Mennonite in Lancaster County with no computer, and no television, only to become a Digital Forensic Analyst and Incident Response Specialist living in New York City, has been quite a journey. My friends tell me the uniqueness of my life requires a blog, but I tell them, I haven't changed much, really.

Personal blog, nothing on here represents my employer.

About DFIR - Moar!

I’m overdue for an update, so here we go!  I came across some pretty cool stuff recently.  I know I’ve said this before, but it really is a fantastic time to be involved in DFIR!

Nick Caldwell won me over with the very first article of his I came across, and he hasn’t disappointed me since!  He’s such a solid force of wisdom: 

The Worst Career Advice I Ever Received

Unless you live in a cave, you probably already knew this, but Eric Zimmerman has a new tool out, looks amazing!  KAPE - Kroll Artifact Parser and Extractor 

I came across this “Malware Dynamic Analysis” nugget by Veronica Kovah, one of so many great and FREE training resources available on 

Microsoft Security Intelligence puts out an annual Report, guess I knew that but forgot about it.  Really enjoyed this most recent one! 

Microsoft's Annual Security Intelligence Report

Podcasts worth mentioning: 

CISO-SecurityVendor Relationship Podcast with David Spark and Mike Johnson:

Defense in Depth Podcast with David Spark and Allan Alford:

Simple Leadership Podcast: 


World Class Investigator Podcast: 


Human Factor Security Podcast: 


The OSINT Podcast: 


Hackable Podcast by McAfee:

Inside Intercom Podcasts: 

ATM Malware Tracker: (Caution Malware!)


13 Cubed DFIR Learning Series: 


Now you can grab it here

Updated BelkaSoft, Carnegie Mellon, and eForensics training listings.

Sunday, January 27, 2019

About DFIR - Catching Up

I took some time this weekend to catch-up a bit with AboutDFIR and add some of the content I've been too busy to share.  I've got tons more, so that will be coming as time allows.  I know Devon has stated it, but I'll reiterate, the links that we add often have context and so I've decided to take a few minutes to add some backstory around the new additions I've made this weekend.

First, under "Certifications and Trainings", I've added the free class The Cuckoo's Egg Decompiled that Chris Sanders gives (yes free, and yep, "the" Chris Sanders!).  Not sure how that wasn't already on here, but hey, now it is, so don't miss that one!  Next, under CTF's (one of my favorite categories), I've added two really cool links from a wonderful gentleman, Mr. John York, whom I met last month while playing the phenomenal "Holiday Hack" that Ed Skoudis and the CounterHack team puts together every year.  John has not only won the annual "Holiday Hack" in the past, he's placed in other years as well.  He teaches at the Shenandoah Valley Governor's School, and has put a unique spin on "Holiday Hack", using it to teach his students about cyber security: KringleCon Lessonized and Holiday Hack 2017 Lessonized.

Then, also through playing "Holiday Hack", I met Mr. Jim Kirn who told me he really likes a tool called OSquery, so I added that under "Intelligence Portals".  And, one more friend I met through "Holiday Hack" (you really need to play that CTF because you make so many wonderful friends) is Mr. Mike Felch.  I actually met Mr. Felch through playing "Holiday Hack" last year, but we reconnected again this year and I realized he is part of the CoinSec PodCast, so check that out.

For all the OSCP fans out there, I came across a real gem that's really gonna help you "Try harder", and he's from my hometown!  I can't wait to buy him a soda next time I'm in Lancaster, PA!  Shout-out to Mr. Michael LaSalvia and his Youtube Channel: Path to OSCP - he's got other really great videos on there as well.  He's totally passionate and such a great teacher!

Then, there's the Google Phishing Quiz that was all over Twitter this past week, so I stuck that under the "Malware Analysis" section. I also learned about yet another ISAC, the Health-ISAC, so I added that one along-side all the others we have listed.

Lastly, I had the great privilege of sitting down to lunch with Evan Gaustad who used to work for Target and has now branched out on his own. Evan is no stranger to the stages of large conferences and it's not every day that I get to chew the fat with someone of his ilk, so that was a really great treat. Evan told me how much he really likes using  LogicHub  and so I added that tool under "Intelligence Portals".

Saturday, December 15, 2018

HolidayHack 2018 CheatSheet

SANS HolidayHack 2018 is going to drop any hour now.  I've compiled a list of tips that I've come across to help get you started.  Enjoy!

Wednesday, September 26, 2018

DFIR Field Manual?

“Investigating Windows Systems” by Harlan Carvey was a great read on so many different levels for me. After binge-reading it over a weekend, I was so excited about it that the following Monday morning I found myself almost shouting at warp-speed to a co-worker about why it was such an important read.  Our chat reminded me of something I had thought about while still making my way through the book.  How could a book so compact, contain that much valuable information?!  I actually believe this book could have been titled, “DFIR Field Manual”, or “DFIRFM.”

For one thing, the book was easily digestible.  At times, I found myself “playing along”, almost like a CTF.  That’s because the book takes you (step-by-step) on an analyst’s journey through several investigations, and invites you to follow-along by downloading all the free images and open source tools the author is using to walk you through.  You get to learn alongside a seasoned veteran, almost in real-time, and observe, even as critical case decisions are being made along the way.

The book felt really timely to me.  I’d recently been following some thought-provoking discourse around the pronounced differences between the “DF” and “IR” of “DFIR” - Digital Forensics and Incident Response, and have even myself gotten into some rather animated discussions during time-sensitive incidents asking, “Where’s our DirListing?!” or, “May I please just have a DirListing!”

The book had a recurring theme for me, and that was, the steps you take regardless of the type of investigation, are often consistent.  Why?  Low hanging fruit!  My take-away was that Harlan almost always makes a visual inspection of the data before he does anything else.  That is not just to verify that he has an image that isn’t damaged, but it’s also so that he can identify outliers rather quickly, such as a batch file sitting in the root of C:\ - might be nothing, but could be something.  Things that make you go, “hmmm”.

Another important concept I learned was the art of discernment and how critical that can be to your end-goal (which an analyst must keep in mind is often guided by a paying client, not your own curiosity).  So, should you choose to dive down a rabbit-hole, (and we all do), a concise analysis plan will help keep you on track, and he shows you how.

As our digital landscape continues to grow, and the average size of hard drives (and memory) gets larger and larger, sometimes it can seem like we’re trying to “boil the ocean”.  To combat that, Harlan teaches us the art of timelining and how that process can help you streamline your analysis by distilling down the data and filtering out the noise.  Additionally, we learn that we have tiered options in our approach, so that we don’t lose meaningful data by doing so; mini, micro, and even nano timelines.

I also learned how to “fail fast”.  Trust me, when you have a client or upper management breathing down your neck for answers, you’ll be glad you grasped that concept.  Regardless of how long you’ve been in the field, you will be astounded at the knowledge you acquire from this book.  New folks might learn not to assume that malware or “hacking tools” simply sitting on a system, are bad.  On the contrary, they’ll become proficient in how to prove whether or not those tools were launched, and how they might have been used.  Or, what local accounts on a system with no profile might mean, and how FTP being run from a browser might be overlooked as it leaves fewer artifacts and in “unusual” places.  Even TimeStomping is covered, as well as using the “Conversations” filter in WireShark to “Follow Stream”.  It’s all there!

The book also tackles another topic I’ve been seeing articles around recently – Sufficiency.  How much data is enough data for us to come to our analysis goals?  Lately that’s been on a lot of people’s minds.  Well, perhaps that answer depends.  For example, have we answered the questions the (paying) principal has asked of us?  It also pivots on another very important case concept – have we, as the investigator, helped our client ask the right questions, because they don’t always know themselves what questions they need to be asking.  If so, and we’ve come to a solid conclusion, then yes, we can confidently state that “our work here is done!”  Even more so, if the principal cannot articulate those questions, and in fact leaves you with almost no information to begin your quest, how do you still make magic happen?  Those answers are all in the book, and the reader is steadily guided through every scenario.

You’ll learn what persistence can look like, and how to spot it.  You’ll grasp what the artifacts of “staging” resemble, whether it’s being done by an advanced adversary, or an insider who’s ready to bolt.  You will also learn how not to allow your own analysis to create a red herring in your case, in other words, if you detonate a piece of malware from the Desktop of your VM, you need to understand that you might be building artifacts that would not be present had it been introduced via its native vector (email, URL, USB), and what those are so you don’t include them in your findings.  You might even find a new trick for using Calc.exe.

I also learned a new thought process around triaging malware that I hadn’t read before and found it to be quite clever.  Execute the sample, let it run for a bit, then shut the box down and grab an image.  Then you can perform analysis to examine the complete file system after the malware runs.  Perhaps not all incidents have time for that, but I thought it was a brilliant methodology.  I typically use RegShot or other tools to snapshot the Registry state before (and after) I run a sample, but now I no longer need to chance missing anything that the malware might have changed.

In conclusion, it truly is fascinating how much ground the book covers in such a concise manner, which I believe can only be attributed to the author being both an accomplished writer, and a seasoned investigator.  Whether you’re running-to-ground File System Tunneling, WindowsXP, Windows10, a Web Server running iis or Apache, it’s all covered in the book, and with log locations and examples.  You. Will. NOT. Be. Disappointed!

Tuesday, June 19, 2018


Photo Credit: My co-worker’s mug, taken with permission for use.

Today I'm releasing my guide on data leakage and IR in the cloud.  I was incredibly inspired by Ed Skoudis’ portion of the 2018 SANS RSA Keynote entitled, “The Five Most Dangerous New Attack Techniques.”  In his keynote, Ed talked about our increasing collaboration with cloud based tools and repositories.  Some examples were Amazon AWS/S3, Docker Hub, GitHub, Google Cloud and Microsoft Azure.  Ed reminded us that we’ve seen some pretty serious “oopsies” from several high profile entities over the past year (Time Warner, Uber, U.S. Army, Verizon), and that data exposure can happen from something as mindless as a misconfiguration of a private repository marked as public or even a public repo mistakenly containing sensitive data.  The talk was so popular, there’s since been a SANS follow-up webinar (also posted at the aforementioned link).  Grab my new paper here, hope you enjoy it!

Friday, August 25, 2017

Homegrown Hunt: You Can Do This! (or How to Think Like a RAT!)

Preamble and Assumptions:

1. Before we begin, this post won’t by any means try to define Hunt.  There are already hundreds of articles arguing about what that term means, this isn’t one of them.  I use the word sprinkled throughout quite loosely and you are free to take poetic license of your own while reading.

2. This is by no means an exhaustive guide to hunt; hunt never ends, it evolves daily, sometimes hourly. The following is meant to simply get you started thinking about some easy, low-hanging fruit, so that maybe you’ll want to take it further. There’s so much more that I could have included, but as someone I respect and look up to recently taught me, “MaryEllen, don’t let perfect be the enemy of good!”  In other words, at some point you just have to cut bait and drop it, hook, line and sinker, or you’ll never publish it!

3. Regardless of the maturity level of your enterprise, work with what you have.  At the end of the day, if you read the following and it affords you the opportunity to increase the security posture of your organization even a little, everybody wins!

4. Some of the concepts mentioned below are from brainstorming sessions with someone far smarter than me, my long-time friend and colleague, Lawrence Judd.  Thank you Lawrence.  I strive to be at your level every single day, and it’s a privilege to call you friend.  Lawrence is wicked smart, and sometimes when I’m chatting with him, I find myself harkening back to one of my first conversations with a NYC building Superintendent.  He would tell me, “MaryEllen, if you want to catch a rat, you have to think like a rat, behave like a rat, and sometimes even pretend you ARE a rat!”

5. I’m finally digging through all the stuff I learned at BlackHat and DEF CON, and you may see some of that referenced below.  Enjoy!

Let’s Dive In!

Bytes In vs. Bytes Out (Producer-Consumer Ratio, or PCR) from Robert M. Lee and David J. Bianco’s BlackHat presentation:

  • See slide #12.  One way to implement that might be to run a daily script that calculates the bytes-in vs. bytes-out per endpoint (PCR). When you do that over time, you can begin to compare the data and look for blips which could indicate someone was staging, i.e. planning to leave in a couple weeks and siphoning a bunch of stuff out.  I've worked in companies where they had v.v. expensive tools that could track all of those types of behaviors, but if the security posture (or budget) within your organization is still maturing, get down in the weeds and write your own, you can do this!
  • There are a couple other slides in David and Robert's deck that I would like to try to turn into use cases as well. 
Moving on - Ground Speed; badging/access logs, including but not limited to:

⇨If I physically badge into an office in North America but then log into the network later that day from the APAC region, whassup?

⇨If I log into the network from the APAC region, but then later that same day I physically badge into an office in North America, whassup?

⇨If I log into a system in North America and then later that day I also log in from the APAC region, whassup?

Login time behaviors oddities:

⇨For example, let’s say someone almost always works 8am-4pm but now all of a sudden they are logged in at 2am, whassup?

Don’t just monitor your logs for unsuccessful logins, also track successful logins, but with correlation, for example, did any of those unsuccessful login attempts just log in, or was there a successful login from an account we have no record of?  Just today, FS-ISAC warned that credential stuffing/ATO attacks are at an elevated level and there is a huge uptick in brute force attacks attempting to leverage stolen credentials. They suggested a possible defense around that would be to monitor your Call Center for increases in account lock-outs.

If you have Splunk, take a look at Shannon Entropy via the following 
(if you don’t have Splunk, try to see how you can improvise using other tools):

Also with Splunk, take a look at the following (again, if you don’t have Splunk, try to see how you can improvise using other tools):

Huge shout-out to Google Chrome’s Andrew R. Whalley who I had the great fortune of meeting at BlackHat.  I was invited to a small group where Mr. Whalley was discussing browser security and some interesting trickery such as Unicode characters and xn--, some of which are outlined here, and here. There are nuggets in both URL's to begin building alerts for.

Office products (Word, Excel, PowerPoint, etc.) probably shouldn’t be spawning .exe, cmd.exe, PowerShell, and a host of other items, for example.

You can hunt down private domain registrations so as to properly investigate, triage and submit for takedown.  I attended a Lunch and Learn in June at the SANS Austin Summit by DomainTools that specifically talked about just that, it was fascinating.  Lunch and Learns aren't recorded and don't always release a slide deck afterward, but I found a free video on the DomainTools Web site which is similar to the talk they gave in Austin.  If you advance the video to exactly 15 minutes in, at the "Hunt Case Study" section, they discuss work-arounds/pivots for private registrations.  It's not in the video link, but at the Lunch and Learn they were even showing how you could pivot off of Google Analytics code to see if anyone else had used it.  I wish I had taken better notes, but I was pretty fried at that point from the malware 610 class I was taking...the video link is close to what was in their talk, just start at exactly 15 minutes in, at "Hunt Case Study."

Track anomalies in CarbonBlack, NetWitness, Splunk, Tanium or a million other other tools, including but not limited to:

o Large outbound files.
o Outbound .rar and .tar files.
o Traffic to high risk geo locations such as .cn, .nk, .ru, .su, tr, etc.
o Traffic from any of the top 20 in your APL reaching-out to high risk locations such as .cn, .nk, .ru, .su, .tr, etc.
o Traffic to odd TLD’s such as .xyz, .sex, .sexy, .xxx, etc.

Applications running which have a hash that’s different than all known good application hashes in the enterprise.

Detecting MimiKatz running in memory:

  • If I understood the author correctly, regardless of what process MimiKatz is injected into, it needs both of these to run: vaultcli.dll and wlanapi.dll.

Known Web Server apps being launched from non-standard locales:

o apache.exe where path is NOT: c:\oracle\program files\apache
o tomcat.exe where path is NOT: c:\program files\tomcat

Track exe’s that could be associated with evil (impersonating the legitimate versions), for example, if any of the following have a running path that is NOT c:\windows  OR c:\winnt (not an exhaustive list):

o aspnet_compiler.exe
o at.exe
o bcdedit.exe
o bitsadmin.exe
o cmd.exe
o conhost.exe
o csc.exe
o cscript.exe
o csrss.exe
o dfsvc.exe
o excel.exe
o expler.exe
o hh.exe
o hkcmd.exe
o IEExec.exe
o iexple.exe
o iexpress.exe
o igfxpers.exe
o igfxsrvc.exe
o ilasm.exe
o InstallUtil.exe
o journal.exe
o jsc.exe
o lsass.exe
o lsm.exe
o MSBuild.exe
o msdt.exe
o mshta.exe
o msiexec.exe
o mstsc.exe
o Net.exe
o Net1.exe
o ping.exe
o PowerShell.exe
o PowerShell_ise.exe
o PresentationHost.exe
o reg.exe
o RegSvcs.exe
o RegSvr32.exe
o rundll32.exe
o sc.exe
o script.exe
o SearchFilterHost.exe
o SearchProtocolHost.exe
o services.exe
o set.exe
o setx.exe
o spoolsv.exe
o svchost.exe
o systemreset.exe
o taskhost.exe
o taskmgr.exe
o vbc.exe
o vssadmin.exe
o w3wp.exe
o winlogon.exe
o winword.exe
o wmic.exe
o Wscript.exe
o wuauclt.exe

Detect single character file name executables, including but not limited to: 0-9.exe and A-Z.exe as well as other characters like ..exe, _.exe, $.exe, etc.

Monitor email for certain file-types within zip, such as .js or scr.

Monitor for encrypted zips.

Check email for .iso, .scr, etc. attachments.

Detect zero-byte files.
o There are several concerns with zero-byte files, some I am sure I am not even aware of, but think of log deletion...files that should contain content but all of a sudden do NOT.  Also, think of destructive malware, which can zero-out files: - there are probably a lot of other things, so if anyone wants to pile on, please do!

Take a look at the SANS “Finding Evil” poster.  Note which processes should never spawn certain other processes, etc. and create rule-sets or dashboards to look for those types of anomalies.  Additionally, this may help you begin tracking known malware injects.

Check the “Behavior Rule-sets” and “Digital Signatures” as outlined in this famous SANS poster.

Monitor what’s being downloaded across the organization.

Correlate hosts that generate greater than one a/v alert within the span of up to one week.

Track a/v hits where the action was “Allowed”, “Deferred”, “Left Alone”, etc.  Create rule-sets for correlation.

Track a/v hits where the action was “Blocked”, “Deleted”, “Quarantined”, etc.  Create rule-sets for correlation.

CarbonBlack offers the following threat indicators:

o Execution from Recycle Bin
o Suspicious process name
o Processes with obfuscated extensions
o Known malware file name
o Execution from System Volume Information folder
o Possible BlackPOS malware registry artifact
o Possible APT backdoor installation
o Possible Ransomware file artifac
o Possible Point-of-Sale malware file artifact
o Execution from APT staging area
o Possible credential theft or misuse
o Possible ZeroAccess activity
o Possible Tibet.c backdoor installation
o Possible wirelurker infection
o ntvdm.exe spawned by office application
o Siesta campaign indicators
o PlugX campaign indicators
o Modification of launchd.conf
o Suspicious OSX persistence mechanism
o Modification of /etc/rc.common
o Possible Olyx/Lasyr activity
o Possible wirenet and/or netweird activity
o Possible Flashback infection
o Possible iWorm infection
o Possible NetWeirdRC infection
o Suspicious local password change
o Attempted osx password hash collection
o Execution from trash bin
o Suspicious process execution
o Suspicious shell activity
o Powershell executed with encoded instructions
o Modification of powershell execution policy
o Possible malicious powershell activity
o Possible WMI Persistence
o Possible WMI command invocation
o WinRM command activity

Begin looking at all the remote access software being utilized in your environment and start to baseline the activity around it. I'm not just talking about Windows built-in RDP, but also tools like GoToMyPC, LogMeIn, TeamViewer, and even Web-Based products such as (to name a few).  These can all be valuable tools but if a SysAdmin has one sitting on his/her server that they didn't install themselves...ummm...gulp.

Lastly, it’s too much to retype it all, but there is a wealth of additional information along the topic of hunt at the following links:

I met Cheryl Biswas at DEF CON a few weeks ago when her laptop malfunctioned as she was taking the stage for her talk. She asked if anyone in the audience had a spare laptop, and guess what, I did...and I gained a wonderful new friendship as well!  Not only is Cheryl incredibly smart, this woman knows her stuff when it comes to Threat Intel and Hunt!  Take a read!

Contains 87 references to Hunt, just search the page for “Hunt”

Contains 21 references to Hunt, just search the page for “Hunt”