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Questions and Answers
What is the main advantage of static acquisition?
Which format is described as a bit-by-bit copy of the drive to a file?
What is a key disadvantage of the raw format?
Which of the following is NOT a term used for a file containing evidence data?
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What feature is commonly associated with proprietary formats?
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Why is live acquisition now preferred over static acquisition?
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Which among the following statements best defines a 'bit-stream copy'?
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What is a limitation of collecting RAM data during live acquisition?
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What is a major disadvantage of proprietary formats in forensic imaging?
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What file extensions are associated with the Expert Witness format?
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What are the design goals of the Advanced Forensics Format?
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Which acquisition method is most common for producing bit-for-bit replications of a drive?
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Why might a bit-stream disk-to-disk method be preferred over a disk-to-image copy?
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What is the main advantage of lossless compression for disk images?
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What is necessary for validating data acquisitions in computer forensics?
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What is the purpose of using MD5 or SHA-1 hashes in compressing disk images?
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What advantage does the USB write-protection feature provide?
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Which of the following is considered a disadvantage when using acquisition tools for Windows?
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What does the RAID 0 configuration primarily provide?
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What is the largest concern when performing RAID data acquisitions?
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What is a primary challenge when making an image of older hardware-firmware RAID systems?
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Which of the following is a limitation of remote network acquisition tools?
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What advantage does ProDiscover Incident Response have over ProDiscover Investigator?
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What does the term 'sparse acquisition method' refer to?
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What is a distinct feature of ProDiscover's PDServer remote agent?
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Which tool is NOT listed as a vendor offering RAID acquisition functions?
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What does the term 'live acquisition' refer to in remote data collection?
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What is one function of the tool NTI SafeBack?
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Which of the following descriptions best describes the DIBS USA RAID?
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What is a primary attribute of the PyFlag tool developed by the Australian Department of Defence?
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What is a significant feature of Runtime Software's disk acquisition utilities?
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What does ProDiscover’s integration with IDS tools allow for?
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Which option describes the main feature of the tool 'WetStone LiveWire'?
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What is a known drawback when using remote acquisition tools?
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Study Notes
Storage Formats
- There are 2 data acquisition types: static and live.
- Static acquisitions involve copying a hard drive from a system that is powered-off.
- Live acquisitions involve copying data from a running computer.
- Live acquisitions are the preferred type because of hard disk encryption and the growing importance of RAM data collection.
- The terms bit-stream copy, bit-stream image, image, mirror, and sector copy all mean the same thing.
Data Acquisition Formats
- The 3 data acquisition formats are: raw format, proprietary formats, and advanced forensics format (AFF).
Raw Format
- Raw format is a bit-by-bit copy of a drive to a file.
- Raw format has advantages: fast data transfers, it can ignore minor read errors from the drive, and most forensics tools can read it.
- Raw format has disadvantages: it requires as much storage as the original disk or data, tools might not collect marginal (bad) sectors, and a validation check must be stored in a separate file.
Proprietary Formats
- Proprietary formats have the option to compress or not compress image files.
- Proprietary formats can split image files into smaller segments and integrate metadata.
- Proprietary formats have disadvantages: they can't share an image between different tools, and each segmented volume has a size limitation.
Advanced Forensics Format (AFF)
- AFF was developed by Dr. Simson L. Garfinkel of Basis Technology Corporation.
- AFF provides compressed or uncompressed image files, has no size restriction, and includes space in the image or segmented files for metadata.
- AFF is open source, has internal consistency checks for self-authentication, and has file extensions .afd for segmented files and .afm for AFF metadata.
Determining Acquisition Methods
- There are two main types of acquisitions: static and live.
- The 4 methods are: bit-stream disk-to-image file, bit-stream disk-to-disk, logical, and sparse.
Bit-Stream Disk-to-Image File
- This is the most common method of acquisition.
- This acquisition method can make more than one copy.
- Copies are bit-for-bit replications of the original drive.
- Tools for this method include: ProDiscover, EnCase, FTK, SMART, Sleuth Kit, X-Ways, and iLook.
Bit-Stream Disk-to-Disk
- This method is used when a disk-to-image copy is not possible due to hardware or software errors, or incompatibilities.
- This method adjusts the target disk’s geometry to match the suspect’s drive.
- Tools for this method include: EnCase, SafeBack, and Snap Copy.
Logical Acquisition and Sparse Acquisition
- Logical acquisition captures only specific files of interest to a case, such as Outlook.pst or .ost files.
- Sparse acquisition collects only some of the data.
Compressing Disk Images
- Lossless compression can compress a disk image by 50% or more.
- Files that are already compressed, like ZIP files, won't compress much more.
- MD5 or SHA-1 hash can be used to verify the image.
Returning Evidence Drives
- In civil litigation, a discovery order might require the return of the original disk after imaging.
- If the disk can’t be retained, make sure the correct type of copy (logical or bitstream) is made.
Contingency Planning for Image Acquisitions
- Create a duplicate copy of the evidence image file.
- Make at least two images of digital evidence using different tools or techniques.
- Make a copy of the host protected area of the disk drive.
- Be prepared to deal with encrypted drives.
Encrypted Hard Drives
- Windows BitLocker and TrueCrypt are used to encrypt hard drives.
- If the machine is on, a live acquisition will capture the decrypted hard drive.
- If the machine is off, the key or passphrase may be needed to decrypt the drive.
Using Acquisition Tools
- Acquisition tools for Windows can make acquiring evidence from a suspect drive more convenient.
- Acquisition tools for Windows have disadvantages: they require a write-blocking device, and they can’t acquire data from a disk’s host protected area.
Windows Write-Protection with USB Devices
- The USB write-protection feature can block any writing to USB devices.
- The target drive needs to be connected to a PATA, SATA, or SCSI controller.
Validating Data Acquisitions
- Validating data acquisitions is the most critical aspect of computer forensics.
- A hashing algorithm utility can be used to validate data acquisitions.
- Validation techniques include CRC-32, MD5, SHA-1, and SHA-512.
- MD5 is not perfect because it has collisions, but it's still widely used.
- SHA-1 has some collisions, but it's better than MD5.
Linux Validation Methods
- dd acquired data can be validated using md5sum or sha1sum utilities.
- dcfldd acquired data can be validated using the hash, hashlog, and vf options.
Windows Validation Methods
- Windows has no built-in hashing algorithm tools for computer forensics.
- Third-party utilities can be used to validate data acquisitions.
- Commercial computer forensics programs have built-in validation features, each with its own technique.
- Raw format image files don't contain metadata, so separate manual validation is needed for raw acquisitions.
Performing RAID Data Acquisitions
- Size is the biggest concern with RAID data acquisitions.
- RAID systems can have terabytes of data.
Understanding RAID
- RAID stands for Redundant Array of Independent Disks.
- It originally used to be "Inexpensive Disks."
- RAID is a computer configuration involving two or more disks.
- RAID was initially developed as a data-redundancy measure.
Understanding RAID 0, 1, 2, 3 and 4
- RAID 0 is striped.
- RAID 0 has rapid access and increased storage.
- RAID 0 lacks redundancy.
- RAID 1 is mirrored.
- RAID 1 is designed for data recovery.
- RAID 1 is more expensive than RAID 0.
- RAID 2 is similar to RAID 1 and writes data to a disk at a bit level.
- RAID 2 has better data integrity checking than RAID 0 and is slower than RAID 0.
- RAID 3 uses data striping and dedicated parity.
- RAID 4 writes data in blocks.
Acquiring RAID Disks
- Some concerns of acquiring RAID disks include: how much storage is needed, what type of RAID is used, do we have the right acquisition tools, can the tools read a forensically copied RAID image, and can the tools read split data saves of each RAID disk?
Acquiring RAID Disks (continued)
- Vendors offering RAID acquisition functions include: Technologies Pathways ProDiscover, Guidance Software EnCase, X-Ways Forensics, Runtime Software, and R-Tools Technologies.
- Sparse or logical acquisition methods can be used to retrieve only data that is relevant to the investigation if the RAID system is too large for a static acquisition.
Using Remote Network Acquisition Tools
- Remote Network Acquisition Tools allow for remotely connecting to a suspect computer and copying data via a network connection.
- Drawbacks of using remote acquisition tools include: potential LAN data transfer speeds and routing table conflicts, difficulties obtaining permissions to access more secure subnets, potential heavy traffic causing delays and errors, and remote access tools being possibly blocked by antivirus.
Remote Acquisition with ProDiscover Investigator
- ProDiscover Investigator can be used to preview a suspect’s drive remotely, perform a live acquisition, encrypt the connection, copy the suspect computer’s RAM, and use the optional stealth mode to hide the connection.
Remote Acquisition with ProDiscover Incident Response
- ProDiscover Incident Response has all of the functions of ProDiscover Investigator plus capture volatile system state information, analyze current running processes, locate unseen files and processes, remotely view and listen to IP ports, run hash comparisons to find Trojans and rootkits, and create a hash inventory of all files remotely.
PDServer Remote Agent
- PDServer is a ProDiscover utility for remote access.
- PDServer needs to be loaded on the suspect computer.
- PDServer can run in stealth mode and can change process name to appear as an OS function.
Remote Connection Security Features
- Remote connection security features include password protection, encrypted communications, secure communication protocols, write-protected trusted binaries, and digital signatures.
Remote Acquisition with EnCase Enterprise
- Allows for remotely acquiring media and RAM data.
- Includes integration with intrusion detection system (IDS) tools.
- Allows for making an image of data from one or more systems.
- Provides the option to preview systems.
- Supports a wide range of file system formats.
- Supports RAID for both hardware and software.
Other Remote Acquisition Tools
- Remote acquisition tools also include R-Tools R-Studio, WetStone LiveWire, and F-Response.
Remote Acquisition with Runtime Software
- Runtime Software offers compact shareware utilities such as DiskExplorer for FAT, DiskExplorer for NTFS, and HDHOST.
- These utilities can be used to create a raw format image file, segment a raw format or compressed image, and access network computers’ drives.
Using Other Forensics-Acquisition Tools
- Other notable forensics-acquisition tools include: SnapBack DatArrest, SafeBack, DIBS USA RAID, ILook Investigator IXimager, Vogon International SDi32, ASRData SMART, and Australian Department of Defence PyFlag.
SnapBack DatArrest
- Columbia Data Products created this MS-DOS tool.
- Can image to SCSI drive, network drive, or disk.
- Fits on a forensic boot floppy.
- SnapCopy adjusts disk geometry.
NTI SafeBack
- A reliable MS-DOS tool small enough to fit on a forensic boot floppy.
- Performs SHA-256 calculation per sector copied.
- Creates a log file.
NTI SafeBack (continued)
- Functions include disk-to-image copy, disk-to-disk copy, copying a partition to an image file, and compressing image files.
DIBS USA RAID
- The Rapid Action Imaging Device (RAID) makes forensically sound disk copies.
- It is a portable computer system designed to make disk-to-disk images.
- The copied disk can then be attached to a write-blocker device.
ILook Investigator IXimager
- IXimager runs from a bootable floppy or CD.
- Designed to work with ILook Investigator.
- Can acquire single drives and RAID drives.
ASRData SMART
- A Linux forensics analysis tool that can make image files of a suspect drive.
- It can robustly read bad sectors on drives, mount suspect drives in write-protected mode, mount target drives in read/write mode, and use optional compression schemes.
Australian Department of Defence PyFlag
- PyFlag is intended for network forensics analysis.
- Can create proprietary format Expert Witness image files.
- Uses sgzip and gzip in Linux.
Challenges of Computer Forensics
- A microcomputer can have more than 60 GB of storage capacity.
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Description
This quiz covers the types and formats of data acquisition in digital forensics, including static and live methods. It also discusses the advantages and disadvantages of raw formats and other acquisition formats. Test your understanding of these crucial concepts in digital evidence collection.
