CFP: Digital Investigation Special Issue on Volatile Memory Analysis

The Journal of Digital Investigation is currently calling for papers for a Special Issue on Volatile Memory Analysis. The Guest Editors of this issue are Michael Cohen (Google) and Bradley Schatz (Schatz Forensic).

We would welcome any novel research into aspects of Volatile Memory Analysis. Submissions are due 31 August 2016.

Memory analysis is a hot research topic with wide applications on many fronts – from malware detection and analysis, to recovery of encryption keys, to user activity reconstruction. As advanced contemporary malware increasingly reduces its on-disk footprint, and adopts increasingly sophisticated host detection subversion mechanisms, memory analysis is currently mainstreaming as a valuable technique for detection and response.

While memory analysis presents many new opportunities, it also presents new complications and challenges, ranging from reliance on undocumented program internals, to atomicity of acquisition methodologies. As memory analysis becomes the status quo methodology the use of directed anti-forensics is also becoming prevalent.

This special issue of the Journal of Digital Investigation invites original research papers that report on state-of-the-art and recent advancements in this rapidly expanding area of enquiry, with a particular emphasis on novel techniques and practical applications for the forensic and incident response community.

Topics of interest include but are not limited to:

  • Malware detection in memory
  • Live memory analysis
  • Live system introspection
  • Memory acquisition
  • Memory analysis of large systems
  • Userspace and application specific memory analysis
  • Cryptographic analysis, key recovery
  • Execution history analysis
  • Data fusion between memory/disk/network

Deadline for submissions is 31 August 2016.


Live Partial Acquisition with Evimetry Wirespeed and EnCase

The Evimetry Wirespeed system enables remote live analysis using your existing forensic toolkit. In doing so, a partial physical image is created. Analysis activity drives the partial acquisition process, which in-turn results in an increasingly complete physical disk image. Acquisition may be incrementally widened to categories of evidence, such as Windows Registries, Log Files, Office documents, Allocated, and all of disk.

An important aspect in balancing live analysis with bulk acquisition is interactive latency (liveness). Unlike any other forensic system, live analysis activities are prioritised over bulk activities, enabling effective live analysis with minimal perceptual delay.

A video demonstrating liveness in partial live acquisition using Evimetry Wirespeed & EnCase  is available on the Evimetry Website. This blog post summarises the salient parts of the video:

@1:08 Partial acquisition of triage artifacts

A partial acquisition of a 240GB SSD1, collecting Page Files, Swap files, Windows Registry Files, Log Files, and Windows Access Traces, is started.

This causes acquisition of volume metadata, followed by filesystem metadata, and then the content data blocks corresponding to these categories. This acquisition completes in 17s and has stored 2.3GiB in the forensic image2.

 

vlcsnap-2016-05-17-16h20m11s675

@2:01 Virtual disk sharing

The active partial image is shared as a virtual disk, and mounted in windows as the F: drive. Windows explorer is then used to browse the F: drive, into the F:\Videos\Videos1\ folder. All access of the blocks of the virtual disk come from the forensic image, as the filesystem metadata has already been acquired.

vlcsnap-2016-05-17-16h21m38s145

On traversing to the F:\Videos\Videos1\Videos\ folder, thumbnails are generated by explorer and shown. As the content for these has not yet been acquired, the underlying blocks are loaded from the suspect drive, stored in the partial image, and then passed on to windows via the iSCSI virtual disk emulator. From there windows explorer renders the thumbnails.

@2:37 Third party application access

The file Mario1_500_HQ_512kb.mp4 is accessed, which contains a mario runthrough video from archive.org. This causes the video to be played using VLC.

The purpose of this is to create an interactive acquisition load on the target drive (recalling that the content of this file have not yet been acquired).

vlcsnap-2016-05-17-16h22m15s984

@3:03 Virtual disk access using EnCase.

The virtual disk is loaded into EnCase3, which scans the volume metadata, and filesystem metadata (in this case parsing the MFT).

The volume metadata and MFT are loaded from the partial image. Interactive performance of the video is unaffected, with no glitches or pauses.

vlcsnap-2016-05-17-16h22m42s893

@4:40 Interactive analysis with EnCase

Within EnCase, the files are filtered down to JPEG files, and the view shifted to Gallery. All of the pictures displayed on the gallery are loaded from the suspect hard drive, and stored in the partial image on their way to EnCase. At this stage only VLC and Encase are competing for access to the target device, and interactive performance of the video is unaffected. There are no glitches or pauses, and load and display of the pictures in EnCase is snappy.

vlcsnap-2016-05-17-16h23m09s312

@5:08 Acquisition scope widened to all of Allocated

A successive partial acquisition operation is started, widening scope to all allocated files. This will only read blocks of files on the target device that aren’t already in the image (a significant portion of the video, and the pictures that were viewed in the gallery are already present in the image, in addition to the volume and filesystem metadata, system logs, registries, etc).

vlcsnap-2016-05-17-16h23m29s895

@5:48 Gallery browsing under high acquisition load

The gallery is scrubbed to a random point, causing acquisition and display of a number of as yet un-accessed images. While this interactive process is competing with the video and the batch acquisition (and proceeding at 238 MB/s), interactive latency has increased but still acceptable.

vlcsnap-2016-05-17-16h24m12s765

@6:00 Single file browsing under high acquisition load

Encase is switched to the Table browser, and random pictures browsed. Interactive latency for single file access is snappy.

vlcsnap-2016-05-17-16h24m40s584

@8:08 Video runthrough completes

Acquisition of 61GiB has completed when the video completes playing.

vlcsnap-2016-05-17-16h32m32s507

@ finish

At the point where this screencast ends, acquisition of allocated space is still underway. The analyst needn’t wait for its completion, as a partial forensic image may be completed at any time, with the resulting image still accessible using regular forensic tools. With the volume & filesystem metadata, and the file content that has been acquired to that point, forensic tools will still be able to interpret the disk. Blocks that were not acquired simply show up as unknown data.

Conclusion

This blog post summarised the most important parts of the video, the purpose of which was to demonstrate:

  • The incremental nature of partial acquisition using Evimetry Wirespeed;
  • The ease of human-in-the-loop live analysis in driving forward partial acquisition;
  • The performance of the Evimetry Wirespeed system.

 


 

1 around 50% full, content including a Windows OS folder heirarchy (no user profiles), random data, and multiple copies of the GovDocs corpus, and videos downloaded from archive.org.
2 We note that this dataset actually doesn’t have any page files or swap files in it.
3 EnCase is a trademark of Guidance Software and has no affiliation with Schatz Forensic.


Introducing Evimetry: digital forensics at wire speed

Digital forensics is full of waiting. Waiting for acquisitions to complete. Waiting for images to process. Waiting for flights and waiting in data centres.

We set out to remove this wait.

In November 2014, Schatz Forensic quietly opened a beta program for a new forensic tool aimed at speeding forensic workflow. The innovative system accelerates acquisition and processing of evidence and closes the gap between acquisition and analysis.

A long beta program has allowed us to listen to our testers, and target the pain points in their forensic process. Practitioners love the faster acquisitions and processing, and cutting hours of wait time from cases. Incident responders are excited by travel-free remote live analysis, and rapid partial imaging of high value artefacts.

Today marks the general availability release of Evimetry Wirespeed. If you are ready for a more efficient workflow and less waiting, visit http://evimetry.com or contact us.


Was the firewall blocking traffic? Identifying active firewall rules using registry analysis.

I came across this question recently in relation to claims that access to a Windows 8 host via Windows Remote Desktop Protocol was blocked by the firewall configuration. This post describes my research into the registry artefacts related to answering the question, and provides a patch to RegRipper to assist in analysis.

Theory of operation

Windows 8 uses the same firewall configuration entries used by Windows 7. Windows ships with a number of firewall rules enabled, and these may be added to or modified by the user, for example using the windows firewall control panel applet.

image

Rules are scoped by Profile, which is either Public, Private, or Domain. Note that I am going to refer to these are a “Network Category” herein, for reasons that will become apparent. These Network Categories (profiles) are associated with particular networks: for example, in the window capture below you can see that my home wireless connection is a “Private network”. For a “Private Network”, firewall rules with a value of “Private” will be applied.

image

The firewall rules are stored in the registry at HKLM\System\CurrentlControlSet\Services\SharedAccess\Parameters\FirewallPolicy\FirewallRules\.

image

The value of the rule above for “RemoteDesktop-UserMode-In-TCP” is

v2.20|Action=Allow|Active=FALSE|Dir=In|Protocol=6|Profile=Public|LPort=3389|App=%SystemRoot%\system32\svchost.exe|Svc=termservice|Name=@FirewallAPI.dll,-28775|Desc=@FirewallAPI.dll,-28756|EmbedCtxt=@FirewallAPI.dll,-28752|

Comparing this the applet above, we can see that this corresponds to the disabled RemoteDesktop-UserMode-In-TCP rule. Looking for the second TCP related RDP, I found the following rule with the key name “{6AFE835E-629E-48DA-A87E-AB6C367D2BB7}”, which corresponds to the similar rule that is enabled for both Private and Domain.

v2.20|Action=Allow|Active=TRUE|Dir=In|Protocol=6|Profile=Domain|Profile=Private|LPort=3389|App=%SystemRoot%\\system32\\svchost.exe|Svc=termservice|Name=@FirewallAPI.dll,-28775|Desc=@FirewallAPI.dll,-28756|EmbedCtxt=@FirewallAPI.dll,-28752|

Observation: Identifying the Category

Existing theory around mapping active networks from the registry is generally accepted: network profiles are stored in HKLM\Software\Microsoft\Windows NT\CurrentVersion\NetworkList\Profiles\. The RegRipper networklist plugin interprets the contents of this registry sub tree.

What my review of the current literature didn’t reveal is how to identify whether a Network Profile is configured as “Private”, “Public”, or “Domain”. Hence, I started looking for automated ways configuring a network in such a manner, from which I hoped to identify the relevant registry keys.

The  documentation for the PowerShell “Set-NetConnectionProfile” command lists the following parameters for the “-NetworkCategory” arguments:

Specifies an array of category types of a network. You cannot set the DomainAuthenticated type by using this cmdlet. The server automatically sets the value of DomainAuthenticated when the network is authenticated to a domain controller. The acceptable values for this parameter are:
– Public
– Private

I opened up powershell and issued the following command.

PS C:\Users\bradley.SCHATZFORENSIC> Set-NetConnectionProfile -interfacealias “WiFi 3″ -NetworkCategory Public

On running this, we see the Network and Sharing Centre applet immediately updated to indicate that the network was now a Public Network.

image

Examination of the associated profile shows a registry key called Category. Based on the naming of the powershell argument “NetworkCategory”, I hypothesised that the Category key might contain the value of relevance. In this instance it was set to a value of 0.

image

I opened then issued the following command.

PS C:\Users\bradley.SCHATZFORENSIC> Set-NetConnectionProfile -interfacealias “WiFi 3″ –NetworkCategory Private

On running this, I saw the Network and Sharing Centre applet immediately update to indicate that the network was now a Private Network.

image

Refreshing the registry viewer, the value of the Category key was now 1.

image

I undertook the above for three iterations and observed the same changes every time. I additionally attempted to undertake a Remote Desktop session while both settings were in place. The outcomes were consistent with the description of the above Firewall Rules. When the network was configured as private, I was unable to establish a connection, and when it was configured as public, I was able to establish a Remote Desktop session.

Hypothesis formulation

At this point my hypothesis was that the value of the Category key corresponded to the Network Category of a network profile. That is:

0 == Public

1 == Private

Of course, this hypothesis could be wrong: what if what I was observing was just one of many configurations occurring as a result of the powershell command?

Accordingly, I undertook an experiment to confirm both these interpretations of the values, and their application of the corresponding firewall rules.

Testing

I manually edited only the Category key of corresponding Network Profile and set it to 0. I restarted the Windows Firewall Service, at which point, I saw the Network and Sharing Centre applet immediately update to indicate that the network was now a Public Network. I attempted to establish a Remote Desktop session, which failed.

I then manually edited the Category key and set it to 1. I restarted the Windows Firewall Service, at which point, I saw the Network and Sharing Centre applet immediately update to indicate that the network was now a Private Network. I attempted to establish a Remote Desktop session, which succeeded.

I undertook the preceding experiment 3 times and received the same result each time.

 

Automation

I modified the networklist.pl plugin of RegRipper to interpret the Category key per the above theory. A third value of the “Category” key was observed: the value of 2. Based on context in which it came up I have inferred that it refers to a Network Category of Domain. I have not tested this.

Conclusions

I didn’t undertake an exhaustive literature review in regard to the above research, so it may well be that this registry artefact has already been treated elsewhere. Please do let me know if I have missed any prior work that you are aware of.

The updated networklist.pl script is currently in my GitHub branch of RegRipper.

I encourage you to validate this new version of networklist.pl against your own registry and let me know if it is consistent with your running configuration, or not.

 

UPDATE: Harlan Carvey has merged this patch into the main RegRipper development tree at GitHub.


Zone Identifier Internals

The “Zone.Identifier” file is a common artefact observed when undertaking forensic examinations of Windows systems. More correctly, this isn’t a file. Rather, it is an Alternate Data Stream (ADS), attached to content downloaded from the internet by Internet Explorer. The stream’s purpose: to record the source of the file so that judgements about its level of trust can later on be made by the Windows OS, particularly when running downloaded executable files.

Raymond Chen describes using windows API’s to access this, and points to further background on this artefact.


CFP: Digital Forensics of Embedded Systems

The Journal of Digital Investigation is currently calling for papers for a Special Issue on Digital Forensics of Embedded Systems. The Guest Editors of this issue are Pavel Gladyshev, Ronald van der Knijff & Bradley Schatz.

We would welcome any novel research into aspects of digital forensics of embedded and mobile computing devices. Submissions are due 1 October 2013.

UPDATE: The due date for submissions for this CFP has been extended to 20 February 2014.

 

The Journal of Digital Investigation covers cutting edge developments in digital forensics and incident response from around the globe.

We welcome submissions for a special issue on Embedded Systems.

The issue will focus on the challenges presented to digital forensics and incident response in the shift from commodity monolithic operating systems and hardware platforms to bespoke and embedded computing devices.

We seek submissions including case studies, practitioner reports of what works in practice, survey articles covering state-of-the-art and future needs, objective tool reviews, and relevant legal analysis. We are also looking for work that proposes possible normalization and standardization in this area.

Deadline for submissions is 20 February 2014.

Visit the journal page for more information and to contribute to this special issue.
http://www.journals.elsevier.com/digital-investigation/call-for-papers/
An embedded system is a computer system that controls operation of a special purpose machine or device, such as

  • automobile engine, brakes, navigator,
  • mobile phone,
  • SCADA/ICS device,
  • smart meter,
  • CCTV camera  recorder,
  • toy,
  • washing machine,
  • mini PABX,

Individual embedded systems are becoming increasingly networked forming the foundation of what is now called smart homes and smart cities. Being part of everyday human activities, embedded systems can be an important source of evidence in digital investigations.

The embedded systems range in complexity from primitive controllers with well defined, fixed functionality, to 32-bit systems capable of running full versions of Linux or Windows.  Most embedded systems are proprietary, bespoke systems, whose interfaces, data structures and internal operation are protected by NDAs.  As a result, the extraction and interpretation of the data from such systems is a major challenge of embedded system forensics.

Embedded systems are increasingly employed for acquisition & analysis tasks in forensic practice. There may be novel forensic applications of embedded systems with the potential to greatly enhance the efficiency of investigations.

In an effort to increase understanding and advance the state of the art, this special issue is dedicated to presenting the varying views regarding digital forensics of, and with, embedded systems.
Submit a case study, survey paper, tool review, or other contribution now.
Visit www.elsevier.com/locate/diin for more information.


Mobile phone forensic analysis–analysis of JTAG and Chip Off images of Android YAFFS Flash

On 18 October 2012 I presented, at the Breakpoint 2012conference, some preliminary results of research I have been undertaking in the area of forensic acquisition and analysis of mobile phones. Specifically I have been focusing on Android phones using NAND flash memory and the YAFFS2 file system. The seminar principally addressed methods of acquisition (JTAG and Chip Off) and the fundamental challenges of reconstructing YAFFS2 file systems from said acquisitions. The slides from the presentation can be found here.

 

Object Headers Slide Screenshot

If you are currently undertaking work in this area and having trouble interpreting any flash images, I would be happy to hear from you.


Android forensic analysis lecture at Breakpoint2012 (AU)

I will be presenting a lecture on Android forensics, focusing on flash acquisition and YAFFS2 filesystem analysis at the Breakpoint 2012 conference in Melbourne, Australia, this October 18.

The speaker lineup is looking fascinating, with leaders in the area of mobile security (both IOS and Android), hardware reverse engineering and Windows internals being on my list of lectures to attend.


Digital forensic evidence chapter published in Expert Evidence text

My chapter on digital evidence has recently been published in the Australian authority on Expert Evidence. The chapter joins technical treatment of over 75 other areas of expert evidence.

The chapter aims to inform the legal professional and fact finder as to the foundations, context, principles, practices, limitations and challenges of the field of digital forensics, in order that they may understand the field enough to effectively engage with the digital forensic expert. It is anticipated that this chapter will additionally be of interest to practitioners and researchers in the field.

The chapter is currently available only to subscribers of the loose leaf service and online via Westlaw AU and Thomson Legal Online. The chapter will be individually purchasable via the above website in due course; if you wish to purchase a copy in the short term, please contact Thomson Reuters via email.


Digital Evidence and Computer Crime 3rd edition – book chapter in press

I just received in the mail an author’s advance copy of Eoghan Casey’s "Digital Evidence and Computer Crime". Originally published in 2000, this update sees the book now in its third edition. Amongst a wide range of significant updates  is a chapter Eoghan and I co-authored. The focus of the chapter is on methods of conducing digital investigations.

Identifying methods of reliably transitioning from investigative goals or claims to substantiated facts has been a significant preoccupation within the field over the last decade. Perspectives have ranged across extremes: from those that deny such methods exist (“it’s an art”) to those that attempt to characterise method as a system or recipe  (“it’s a process”). Only in recent years have clear inroads been made into the relationship between digital forensics and the scientific method in general.

The chapter begins with a comparison of a wide range of perspectives on digital investigation methodologies, and follows with practical guidance on applying the scientific method as a methodology for each step of a digital investigation. The chapter concludes with an investigative scenario demonstrating how the scientific method may be applied in the context of an actual case.