Difference between pages "Encase image file format" and "Research Topics"

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The Encase image file format is used by [[EnCase]] used to store various types of digital evidence e.g.
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Interested in doing research in computer forensics? Looking for a master's topic, or just some ideas for a research paper? Here is my list. Please feel free to add your own ideas.
* disk image (physical bitstream of an acquired disk)
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* volume image
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* memory
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* logical files
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== History ==
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==Research Projects==
Expert Witness (for Windows) was the original name for EnCase (dating back to 1998). More info about this can be found on the Internet Archive [http://web.archive.org/web/19980504153628/http://guidancesoftware.com/] including a demo of the original software [http://web.archive.org/web/19980504153759/http://guidancesoftware.com/data/ewsetup.exe].
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===Flash Forensics===
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Flash storage devices offer opportunities for recovering information that is not visible by going beneath the logical layer visible to users and most operating systems.
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* Access the physical layer of SD cards and/or USB flash devices. Reverse-engineer the Flash Translation Layer to find deleted data and files.
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''Necessary skills: social engineering the flash vendors; kernel programming; reverse-engineering.''
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==Stream Forensics==
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* Process the entire disk with one pass, or at most two, to minimize seek time.
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==Evidence Falsification==
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* Automatically detect falsified digital evidence.
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==Sanitization==
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* Detect and diagnose sanitization attempts.
  
(presumably) the product was renamed because it intruded the Expert Wittness trademark held by ASR Data [http://www.asrdata.com/wp-content/themes/asr/pdf/ruling.pdf].
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==Programming Projects==
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===SleuthKit Enhancements===
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[[SleuthKit]] is the popular open-source system for forensics and data recovery.
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* Add support for a new file system:
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** The [[YAFFS2]] [[flash file system]]. (YAFFS2 is currently used on the Google G1 phone.)
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** The [[JFFS2]] [[flash file system]]. (JFFS2 is currently used on the One Laptop Per Child laptop.)
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** [[XFAT]], Microsoft's new FAT file system.
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* Enhance support for an existing file system:
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** EXT4
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** Add support for NTFS encrypted files.
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** Report the physical location on disk of compressed files.
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* Write a FUSE-based mounter for SleuthKit, so that disk images can be forensically mounted using TSK. (I've already started on this if you want the code.)
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''Necessary skills: C programming and filesystem familiarity.''
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===fiwalk Enhancements===
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* Rewrite the metadata extraction system.
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* Extend [[fiwalk]] to report the NTFS "inodes."
  
The Encase image file format therefore is also referred to as the Expert Witness (Compression) Format.
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==Timeline Analysis==
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Write a new timeline viewer that supports:
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* Logfile fusion (with offsets)
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* Logfile correlation
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* View logfiles in the frequency domain.
  
 +
==Online Social Network Analysis==
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* Find and download in a forensically secure manner all of the information in a social network (e.g. Facebook, LinkedIn, etc.) associated with a targeted individual.
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* Determine who is searching for a targeted individual. This might be done with a honeypot, or documents with a tracking device in them, or some kind of covert Facebook App.
  
Currently there are 2 versions of the format:
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==Cell Phone Exploitation==
* version 1 is (reportedly) based on [[:File:ASR Data's Expert Witness Compression Format.pdf|ASR Data's Expert Witness Compression Format]]
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===Imaging===
* version 2 was introduced in EnCase 7, for which a format specification (at least non-encrypted Ex01) is available, but requires registration.
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* Image the contents of a cell phone physical memory using the JTAG interface.
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===Interpretation===
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* Develop a tool for reassembling information in a cell phone memory
  
The libewf project indicates that the January 2012 version of the version 2 format specification, besides Lx01 not being specified, is sufficient to read non-encrypted Ex01 files.
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==Corpora Development==
Although the format specification is not complete, at the moment Guidance Software is working on an update.
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===Realistic Disk Corpora===
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There is need for realistic corpora that can be freely redistributed but do not contain any confidential personally identifiable information (PII).  
  
== Version 1 ==
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These disk images may be either of an external drive or of a system boot drive. The drive images should have signs of ''wear'' --- that is, they should have resident files, deleted files, partially overwritten files, contiguous files, and fragmented files.
The media data can be stored in multiple evidence files, which are called segment files.
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Each segment file consist of multiple sections, which has a distinct section start definition containing a section type.
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Up to EnCase 5 the segment file were limited to 2 GiB, due to the internal 31-bit file offset representation. This limitation was lifted by adding a base offset value in EnCase 6.
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 +
From DFRWS 2005
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Frank Adelstein (ATC-NY), Yun Gao and Golden G. Richard III (University of New Orleans): Automatically Creating Realistic Targets for Digital Forensics Investigation http://www.dfrws.org/2005/program.shtml
  
EnCase allows to store the data compressed either using a fast or best level of the deflate compression method.
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===Realistic Network Traffic===
EnCase 7 no longer distinguishes between fast or best compression and just provides for either uncompressed or compressed.
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Generating realistic network traffic requires constructing a test network and either recording interactions within the network or with an external network.
 
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Besides digital evidence the evidence files, or segment files, contain a header containing case information.
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The case information which entails date and time of acquisition, an examiner's name, notes on the acquisition, and an optional password.
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* In EnCase 3 the case information header is stored in the "header" section, which is defined twice within the file and contain the same information.
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* As of EnCase 4 an additional "header2" section was added. The "header" section now appears only once, but the new "header2" section twice.
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The format adds error detection by storing the data with checksums (Adler32), for both the metadata as the data blocks, which are by default 64 x 512 byte sectors (32 KiB).
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As of EnCase 5 the number of sectors per block (chunk) can vary.
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EnCase 3F introduced an "error2" section that it uses to record the location and number of bad sector chunks. The way it handles the sections it can't read is that those areas are filled with zero.
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Then EnCase displays to the user the areas that could not be read when the image was acquired. The granularity of unreadable chunks appears to be 32K.
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As of EnCase 5 the granularity of unreadable chunks can vary.
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EnCase 3 can store a one-way hash of the data. For a bitstream it does so by calculating e.g. a MD5 hash of the original media data and adds a hash section to the last of the segment file.
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As of EnCase 6 the option to store a SHA1 hash was added.
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EnCase 5 and later have the option to store '''single files''' into the EnCase Logical Evidence File (LEF) or EWF-L01.
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This format changed slightly in EnCase 6 and 7.
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== Version 2 ==
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In EnCase 7 the EWF format was succeeded by the EnCase Evidence File Format Version 2 (EWF2-EX01 and EWF2-LX01).
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EWF2-EX01 is at it's lower levels a different format then EWF-E01 and provides support for:
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* bzip2 compression
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* direct encryption (AES-256) of the section data
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The same features are added to the new logical evidence file format (EWF2-LX01) with the exception of encryption.
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The actual encryption method and corresponding key derivation are, current, not open.
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EWF2-EX01, EWF2-LX01 are not backwards compatible with previous EnCase products.
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== See Also ==
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* [[:File:ASR Data's Expert Witness Compression Format.pdf|ASR Data's Expert Witness Compression Format]]
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* [[EnCase]]
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== External Links ==
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* [http://encase-enterprise-blog.guidancesoftware.com/2012/01/2nd-generation-encase-evidence-file.html 2nd Generation EnCase Evidence File Technical Specification now Available], Guidance Software, Jan 2012
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* Requires registration: [http://www.guidancesoftware.com/DocumentRegistration.aspx?did=1000018246 EnCase Evidence File Format Version 2], Guidance Software, Jan 2012
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* [http://code.google.com/p/libewf/downloads/detail?name=Expert%20Witness%20Compression%20Format%20%28EWF%29.pdf Expert Witness Compression Format (EWF)].
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* [http://code.google.com/p/libewf/downloads/detail?name=Expert%20Witness%20Compression%20Format%202%20%28EWF2%29.pdf Expert Witness Compression Format (EWF) version 2].
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* [http://www.cfreds.nist.gov/v2/Basic_Mac_Image.html Sample image in EnCase, iLook, and dd format] - From the [[Computer Forensic Reference Data Sets]] Project
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[[Category:Forensics File Formats]]
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Revision as of 08:44, 3 September 2009

Interested in doing research in computer forensics? Looking for a master's topic, or just some ideas for a research paper? Here is my list. Please feel free to add your own ideas.

Contents

Research Projects

Flash Forensics

Flash storage devices offer opportunities for recovering information that is not visible by going beneath the logical layer visible to users and most operating systems.

  • Access the physical layer of SD cards and/or USB flash devices. Reverse-engineer the Flash Translation Layer to find deleted data and files.

Necessary skills: social engineering the flash vendors; kernel programming; reverse-engineering.

Stream Forensics

  • Process the entire disk with one pass, or at most two, to minimize seek time.

Evidence Falsification

  • Automatically detect falsified digital evidence.

Sanitization

  • Detect and diagnose sanitization attempts.

Programming Projects

SleuthKit Enhancements

SleuthKit is the popular open-source system for forensics and data recovery.

  • Add support for a new file system:
  • Enhance support for an existing file system:
    • EXT4
    • Add support for NTFS encrypted files.
    • Report the physical location on disk of compressed files.
  • Write a FUSE-based mounter for SleuthKit, so that disk images can be forensically mounted using TSK. (I've already started on this if you want the code.)

Necessary skills: C programming and filesystem familiarity.

fiwalk Enhancements

  • Rewrite the metadata extraction system.
  • Extend fiwalk to report the NTFS "inodes."

Timeline Analysis

Write a new timeline viewer that supports:

  • Logfile fusion (with offsets)
  • Logfile correlation
  • View logfiles in the frequency domain.

Online Social Network Analysis

  • Find and download in a forensically secure manner all of the information in a social network (e.g. Facebook, LinkedIn, etc.) associated with a targeted individual.
  • Determine who is searching for a targeted individual. This might be done with a honeypot, or documents with a tracking device in them, or some kind of covert Facebook App.

Cell Phone Exploitation

Imaging

  • Image the contents of a cell phone physical memory using the JTAG interface.

Interpretation

  • Develop a tool for reassembling information in a cell phone memory

Corpora Development

Realistic Disk Corpora

There is need for realistic corpora that can be freely redistributed but do not contain any confidential personally identifiable information (PII).

These disk images may be either of an external drive or of a system boot drive. The drive images should have signs of wear --- that is, they should have resident files, deleted files, partially overwritten files, contiguous files, and fragmented files.

From DFRWS 2005 Frank Adelstein (ATC-NY), Yun Gao and Golden G. Richard III (University of New Orleans): Automatically Creating Realistic Targets for Digital Forensics Investigation http://www.dfrws.org/2005/program.shtml

Realistic Network Traffic

Generating realistic network traffic requires constructing a test network and either recording interactions within the network or with an external network.