CHFI Computer Forensics Fundamentals and Process Practice Test 9 — 15 Questions

Question 1

Which of the following is a key requirement for digital evidence to be considered admissible in court?

Accepted Answer

The evidence must be authentic and its integrity must be verifiable. Digital evidence must be authentic and its integrity verifiable to meet the legal standard of admissibility, as established by rules such as the Federal Rules of Evidence (FRE 901) and the Daubert standard. Authentication requires proving that the evidence is what it claims to be, typically through a hash value (e.g., MD5, SHA-1, or SHA-256) computed before and after analysis to ensure no tampering occurred. Without verifiable integrity, the evidence could be challenged as altered, making it inadmissible regardless of how it was collected.

Answer

The evidence must have been collected by a law enforcement officer

Answer

The evidence must be stored on a write-blocked device

Answer

The evidence must be encrypted to ensure confidentiality

Question 2

A first responder arrives at a suspected intrusion scene. A desktop computer is powered on and logged in. The user claims they saw suspicious files being copied to a USB drive. Which of the following should the first responder do FIRST?

Accepted Answer

Capture volatile data such as memory and running processes.. In a live intrusion where a USB transfer is in progress, volatile data (memory, running processes, network connections) is the most ephemeral and will be lost if the system is powered down. Capturing this data first preserves evidence of the malicious activity, such as the process that initiated the copy and any network connections, which is critical for reconstructing the attack. This follows the order of volatility (RFC 3227), which mandates capturing volatile data before non-volatile data.

Answer

Power off the computer immediately to prevent further data loss.

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Photograph the scene and document everything in a notebook.

Answer

Create a forensic image of the hard drive using a write blocker.

Question 3

During a forensic investigation, a lawyer objects to the admissibility of a log file on the grounds that it is hearsay. Which of the following is the BEST argument to overcome this objection?

Accepted Answer

The log file qualifies as a business record exception to the hearsay rule.. The log file is admissible under the business records exception to the hearsay rule (Federal Rule of Evidence 803(6)). This exception applies because logs are created automatically or by a person with knowledge, near the time of the event, in the regular course of business, and it is the regular practice to make such records. In digital forensics, system logs (e.g., Windows Event Logs, syslog) are routinely admitted under this exception, as they are generated by the system without the declarant's bias or memory issues.

Answer

The log file is circumstantial evidence, not hearsay.

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The log file is direct evidence of the intrusion.

Answer

The log file is the best evidence because it is an original record.

Question 4

An investigator needs to acquire data from a suspect's hard drive without altering any data. Which tool is MOST appropriate to ensure write-blocking at the hardware level?

Accepted Answer

Tableau Forensic Bridge (hardware write-blocker). A hardware write-blocker like the Tableau Forensic Bridge sits between the suspect drive and the forensic workstation at the physical layer, intercepting and blocking any write commands (e.g., ATA WRITE DMA, SCSI WRITE) before they reach the drive. This ensures that no data—including metadata, timestamps, or file system artifacts—is altered during acquisition, which is critical for maintaining evidentiary integrity. Software-based blockers can be bypassed by the OS or a malicious driver, making hardware-level blocking the gold standard in forensic acquisition.

Answer

FTK Imager (software write-blocker)

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dd command with 'iflag=noatime'

Answer

EnCase software acquisition module

Question 5

What is the PRIMARY purpose of a chain of custody document in a forensic investigation?

Accepted Answer

To provide a chronological record of who handled the evidence, when, and why.. The chain of custody document is the foundational record that ensures evidence integrity and admissibility in court. Its primary purpose is to create a chronological, unbroken log of every person who handled the evidence, the exact time and date of each transfer, and the reason for the transfer. This directly supports the legal requirement to prove that the evidence has not been tampered with or altered from the moment of seizure to its presentation in court.

Answer

To document the tools used during the investigation.

Answer

To list all the files found on the suspect's computer.

Answer

To authorize the search and seizure of digital evidence.

Question 6

According to Locard's exchange principle, which of the following is TRUE in a digital forensic context?

Accepted Answer

A suspect will always leave traces of their activity on a computer system.. In a digital forensic context, Locard's exchange principle holds that whenever a suspect interacts with a computer system, they will inevitably leave traces of that activity. This can include artifacts such as registry entries, log files, prefetch files, browser history, or metadata, even if the user attempts to delete or obfuscate their actions. The principle underpins the entire field of digital forensics, asserting that digital interaction always produces residual data.

Answer

Only physical evidence, not digital evidence, is subject to exchange.

Answer

Digital evidence is always volatile and cannot be preserved.

Answer

The absence of evidence proves the suspect is innocent.

Question 7

During a forensic examination of a Windows system, the investigator finds a file named 'notes.txt' that contains a list of passwords. The file's last modified timestamp is before the incident date, but its last accessed timestamp is during the incident. Which type of evidence is this file considered?

Accepted Answer

Circumstantial evidence. The file 'notes.txt' has a last modified timestamp before the incident but a last accessed timestamp during the incident. This indicates the file was opened or read during the incident, but not modified. Such indirect evidence suggests the attacker may have viewed the passwords, but does not directly prove the act of using them. Therefore, it is circumstantial evidence because it requires inference to connect the file access to the incident.

Answer

Best evidence

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Hearsay evidence

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Direct evidence

Question 8

An investigator needs to testify in court as an expert witness. Which of the following qualifications is MOST important for the court to accept their testimony?

Accepted Answer

They can demonstrate knowledge, skill, experience, training, or education that will assist the trier of fact.. Under the Federal Rules of Evidence (FRE) Rule 702, a witness qualified as an expert by knowledge, skill, experience, training, or education may testify if their specialized knowledge will assist the trier of fact. Option C directly mirrors this legal standard, making it the most critical qualification for admissibility. Certifications, publications, or years of service are supporting factors but not independently sufficient under the Daubert or Frye standards.

Answer

They have a certification in computer forensics.

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They have published articles in peer-reviewed journals on digital forensics.

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They have been employed as a forensic analyst for over 10 years.

Question 9

A forensic investigator is documenting evidence for a case. What is the PRIMARY purpose of maintaining an unbroken chain of custody for digital evidence?

Accepted Answer

To prove that the evidence has not been altered or tampered with.. The primary purpose of maintaining an unbroken chain of custody is to establish the integrity and authenticity of digital evidence by documenting every person who handled it, every transfer, and every access event. This documentation allows the court to verify that the evidence has not been altered, tampered with, or corrupted from the moment of seizure through analysis and presentation. Without a provable chain of custody, the evidence may be deemed inadmissible under rules like Federal Rule of Evidence 901 or similar standards in other jurisdictions.

Answer

To track the storage location of the evidence.

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To speed up the investigation process.

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To assign responsibility for the evidence to a single individual.

Question 10

Which TWO of the following hashing algorithms are commonly used to verify the integrity of forensic images? (Choose two.)

Accepted Answer

SHA-1. SHA-1 and MD5 are the two hashing algorithms most commonly used in forensic practice to verify the integrity of forensic images. They produce a fixed-size hash value (160-bit for SHA-1, 128-bit for MD5) that acts as a digital fingerprint; if the hash of the original image matches the hash of a copy, the data is considered unchanged. Despite known collision weaknesses, they remain the de facto standards in tools like FTK Imager, EnCase, and dd due to their speed and widespread tool support.

Answer

SHA-3

Answer

RSA

Answer

AES

Question 11

During a forensic investigation, an analyst uses a tool to create a bit-for-bit copy of a hard drive while ensuring the original is not modified. Which of the following is a hardware write blocker that can be used for this purpose?

Accepted Answer

Tableau. A hardware write blocker physically prevents any write commands from reaching the original drive at the SATA/IDE bus level, ensuring the drive remains unaltered during acquisition. Tableau is a well-known manufacturer of forensic hardware write blockers that operate transparently to the imaging software, making it the correct choice for a hardware-based solution.

Answer

FTK Imager

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dd

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EnCase

Question 12

During a forensic examination, an analyst uses the command 'dcfldd if=/dev/sda of=image.dd hash=sha256 hashlog=hash.txt'. What is the primary purpose of including 'hash=sha256' in this command?

Accepted Answer

To compute a SHA-256 hash of the input drive and log it to a file for integrity verification. The `hash=sha256` parameter in `dcfldd` instructs the tool to compute a SHA-256 hash of the input device (`/dev/sda`) during the acquisition process. This hash is then logged to the file specified by `hashlog=hash.txt`, providing a verifiable integrity check that the forensic image matches the original source. This is a standard forensic practice to ensure the image has not been altered or corrupted.

Answer

To split the image into multiple files named with SHA-256 checksums

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To encrypt the output image file using SHA-256

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To compress the image using SHA-256 compression algorithm

Question 13

What is the primary purpose of maintaining a chain of custody during a forensic investigation?

Accepted Answer

To document the handling of evidence from collection to presentation in court. The primary purpose of maintaining a chain of custody is to create a documented, unbroken record of every person who handled the evidence, from the moment it is collected until it is presented in court. This documentation is critical to establish the authenticity and integrity of the evidence, ensuring it has not been tampered with or altered, which is a foundational requirement for admissibility under legal standards like the Federal Rules of Evidence (FRE) 901. Without a proper chain of custody, the evidence can be challenged as inadmissible due to lack of trustworthiness.

Answer

To reduce the size of evidence for easier storage

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To analyze the evidence for hidden data

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To encrypt the evidence to prevent unauthorized access

Question 14

A forensic analyst is preparing to acquire an image from a suspect's hard drive. The analyst connects the drive to a write blocker, then uses FTK Imager to create a forensic image. Which hashing algorithm is commonly used by FTK Imager to verify image integrity?

Accepted Answer

MD5. FTK Imager uses MD5 (Message Digest 5) as its default hashing algorithm to verify the integrity of forensic images. MD5 produces a 128-bit hash value that uniquely represents the data, allowing the analyst to confirm that the acquired image is an exact bit-for-bit copy of the original drive. While SHA-1 is also supported, MD5 is the algorithm most commonly associated with FTK Imager's verification process.

Answer

AES

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RSA

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Blowfish

Question 15

An investigator seizes a computer that was involved in a crime. The suspect claims that the evidence was planted. Which forensic principle best helps to refute this claim by demonstrating that the evidence could only have been left by the suspect?

Accepted Answer

Locard's exchange principle. Locard's exchange principle states that every contact leaves a trace. In digital forensics, this means the suspect's interaction with the computer—such as typing, accessing files, or connecting peripherals—will leave unique digital artifacts (e.g., registry keys, prefetch files, USB device serial numbers, or browser history). By demonstrating that these artifacts could only have been created by the suspect's specific actions or device, the investigator refutes the claim of planting.

Answer

Hearsay rule

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Best evidence rule

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Chain of custody