Tools
Memory Analysis
When I've had the opportunity to conduct memory analysis, Volatility and bulk_extractor have been invaluable.
Back when I started in the industry, oh, lo so many years ago, 'strings' was pretty much the tool for memory "analysis". Thanks to Volatility's strings plugin, there's so much more you can do; run 'strings' (I use the one from SysInternals) with the "-o" switch, and parse out any strings of interest. From there, using the Volatility strings plugin lets you see where those strings of interest are located within the memory sample, providing significant context.
I've run bulk_extractor across memory samples, and been able to get pcap files that contained connections not present in Volatility's netscan plugin output. That is not to say that one tool is "better" than the other...not at all. Both tools do something different, and look for data in different ways, so using them in conjunction provides a more comprehensive view of the data.
If you do get a pcap file (from memory or any other data source), be sure to take a look at Lorna's ISC handler diary entry regarding packet analysis; there are some great tips available. When conducting packet analysis, remember that besides WireShark, you might also want to take a look at the free version of NetWitness Investigator.
Carving
Like most analysts, I've needed to carve unallocated space (or other data blobs) for various items, including (but not limited to) executable images. Carving unallocated space, or any data blob (memory dump, pagefile, etc.) for individual records (web history, EVT records, etc.) is pretty straight forward, as in many cases, these items fit within a sector.
Most analysts who've been around for a while are familiar with foremost (possible Windows .exe here) and scalpel as carving solutions. I did some looking around recently to see if there were any updates on the topic of carving executables, and found Brian Baskin's pe_carve.py tool. I updated my Python 2.7 installation to version 2.7.13, because the pip package manager became part of the installation package as of version 2.7.9. Updating the installation so that I could run pe_carve.py was as simple as "pip install bitstring" and "pip install pefile". That was it. From there, all I had to do was run Brian's script. The result was a folder with files that had valid PE headers, files that tools such as PEView parsed, but there were sections of the files that were clearly not part of the file. But then, such is the nature of carving files from unallocated space.
Addendum, 1 Feb: One of the techniques I used to try to optimize analysis was to run 'strings' across the carved PE files, in hopes of locating .pdb strings or other indicators. Unfortunately, in this case, I had nothing to go on other than file names. I did find several references to the file names, but those strings were found in the files that were clearly part of the sectors included in the file that likely had little to do with the original file.
Also, someone on Twitter recommended FireEye's FLOSS tool, something you'd want to use in addition to 'strings'.
Hindsight
Hindsight, from Obsidian Forensics, is an awesome tool for parsing Chrome browser history. If you haven't tried it, take a look. I've used it quite successfully during engagements, most times to get a deeper understanding of a user's browsing activity during a particular time frame. However, in one instance, I found the "smoking gun" in a ransomware case, where the user specifically used Chrome (was also using IE on a regular basis) to browse to a third-party email portal, download and activate a malicious document, and then infect their system with ransomware. Doing so by-passed the corporate email portal protections intended specifically to prevent systems from being infected with...well...ransomware. ;-)
Hindsight has been particularly helpful, in that I've used it to get a small number of items to add to a timeline (via tln.pl/.exe) that provide a great deal of context.
Shadow Copies
Volume shadow copies (VSCs) and how DFIR analysts take advantage of them is something I've always found fascinating. Something I saw recently on Twitter was a command line that can be used to access files within Volume Shadow Copies on live systems; the included comment was, "Random observation - if you browse c$ on a PC remotely and add @TIMEZONE-Snapshot-Time, you can browse VSS snapshots of a PC."
An image included within the tweet chain/thread appeared as follows:
I can't be the only one that finds this fascinating...not so much that it can be done, but more along the lines of, "...is anyone doing this on systems within my infrastructure?"
Now, I haven't gotten this to work on my own system. I am on a Windows 10 laptop, and can list the available shadow copies, but can't copy files using the above approach. If anyone has had this work, could you share what you did? I'd like to test this in a Win7 VM with Sysmon running, but I haven't been able to get it working there, either.
Addendum, 1 Feb: Tun provided a tweet to Dan's blog post that might be helpful with this technique. Another "Dan" said on Twitter that he wasn't able to get the above technique to work.
As a side note to this topic, remember this blog post? Pretty sneaky technique for launching malware. What does that look like, and how do you hunt for it on your network?
Windows Event Logs
I recently ran across a fascinating MSDN article entitled, "Recreating Windows Event Log Files"; kind of makes you wonder, how can this be used by a bad guy, and more importantly, has it?
Maybe the real question is, are you instrumented to catch this happening on endpoints in your environment? I did some testing recently, and was simply fascinated with what I saw in the data.
When I've had the opportunity to conduct memory analysis, Volatility and bulk_extractor have been invaluable.
Back when I started in the industry, oh, lo so many years ago, 'strings' was pretty much the tool for memory "analysis". Thanks to Volatility's strings plugin, there's so much more you can do; run 'strings' (I use the one from SysInternals) with the "-o" switch, and parse out any strings of interest. From there, using the Volatility strings plugin lets you see where those strings of interest are located within the memory sample, providing significant context.
I've run bulk_extractor across memory samples, and been able to get pcap files that contained connections not present in Volatility's netscan plugin output. That is not to say that one tool is "better" than the other...not at all. Both tools do something different, and look for data in different ways, so using them in conjunction provides a more comprehensive view of the data.
If you do get a pcap file (from memory or any other data source), be sure to take a look at Lorna's ISC handler diary entry regarding packet analysis; there are some great tips available. When conducting packet analysis, remember that besides WireShark, you might also want to take a look at the free version of NetWitness Investigator.
Carving
Like most analysts, I've needed to carve unallocated space (or other data blobs) for various items, including (but not limited to) executable images. Carving unallocated space, or any data blob (memory dump, pagefile, etc.) for individual records (web history, EVT records, etc.) is pretty straight forward, as in many cases, these items fit within a sector.
Most analysts who've been around for a while are familiar with foremost (possible Windows .exe here) and scalpel as carving solutions. I did some looking around recently to see if there were any updates on the topic of carving executables, and found Brian Baskin's pe_carve.py tool. I updated my Python 2.7 installation to version 2.7.13, because the pip package manager became part of the installation package as of version 2.7.9. Updating the installation so that I could run pe_carve.py was as simple as "pip install bitstring" and "pip install pefile". That was it. From there, all I had to do was run Brian's script. The result was a folder with files that had valid PE headers, files that tools such as PEView parsed, but there were sections of the files that were clearly not part of the file. But then, such is the nature of carving files from unallocated space.
Addendum, 1 Feb: One of the techniques I used to try to optimize analysis was to run 'strings' across the carved PE files, in hopes of locating .pdb strings or other indicators. Unfortunately, in this case, I had nothing to go on other than file names. I did find several references to the file names, but those strings were found in the files that were clearly part of the sectors included in the file that likely had little to do with the original file.
Also, someone on Twitter recommended FireEye's FLOSS tool, something you'd want to use in addition to 'strings'.
Hindsight
Hindsight, from Obsidian Forensics, is an awesome tool for parsing Chrome browser history. If you haven't tried it, take a look. I've used it quite successfully during engagements, most times to get a deeper understanding of a user's browsing activity during a particular time frame. However, in one instance, I found the "smoking gun" in a ransomware case, where the user specifically used Chrome (was also using IE on a regular basis) to browse to a third-party email portal, download and activate a malicious document, and then infect their system with ransomware. Doing so by-passed the corporate email portal protections intended specifically to prevent systems from being infected with...well...ransomware. ;-)
Hindsight has been particularly helpful, in that I've used it to get a small number of items to add to a timeline (via tln.pl/.exe) that provide a great deal of context.
Shadow Copies
Volume shadow copies (VSCs) and how DFIR analysts take advantage of them is something I've always found fascinating. Something I saw recently on Twitter was a command line that can be used to access files within Volume Shadow Copies on live systems; the included comment was, "Random observation - if you browse c$ on a PC remotely and add @TIMEZONE-Snapshot-Time, you can browse VSS snapshots of a PC."
An image included within the tweet chain/thread appeared as follows:
 |
| Source: Twitter |
I can't be the only one that finds this fascinating...not so much that it can be done, but more along the lines of, "...is anyone doing this on systems within my infrastructure?"
Now, I haven't gotten this to work on my own system. I am on a Windows 10 laptop, and can list the available shadow copies, but can't copy files using the above approach. If anyone has had this work, could you share what you did? I'd like to test this in a Win7 VM with Sysmon running, but I haven't been able to get it working there, either.
Addendum, 1 Feb: Tun provided a tweet to Dan's blog post that might be helpful with this technique. Another "Dan" said on Twitter that he wasn't able to get the above technique to work.
As a side note to this topic, remember this blog post? Pretty sneaky technique for launching malware. What does that look like, and how do you hunt for it on your network?
Windows Event Logs
I recently ran across a fascinating MSDN article entitled, "Recreating Windows Event Log Files"; kind of makes you wonder, how can this be used by a bad guy, and more importantly, has it?
Maybe the real question is, are you instrumented to catch this happening on endpoints in your environment? I did some testing recently, and was simply fascinated with what I saw in the data.
Tools
Reviewed by 0x000216
on
Tuesday, January 31, 2017
Rating: 5
Reviewed by 0x000216
on
Tuesday, January 31, 2017
Rating: 5
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