CHFI Network and Cloud Forensics — Timed 25 Questions

Question 1

During a cloud forensics investigation, the investigator discovers that the cloud provider uses shared storage for multiple tenants. Which challenge is MOST likely to arise when acquiring a forensic image?

25 minute time limit — choose an answer to begin.

Accepted Answer

Data commingling with other tenants. In cloud environments with shared storage, data from multiple tenants resides on the same physical or logical volume. When acquiring a forensic image, the investigator cannot isolate a single tenant's data without also capturing other tenants' data, leading to data commingling. This violates chain-of-custody and privacy principles, making it the primary challenge.

Answer

Physical acquisition of the storage device is required

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No API access to the storage system

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Inability to decrypt data at rest

Question 2

A forensic analyst is investigating a network breach and finds that the attacker used a technique that bypasses Network Access Control (NAC). Which of the following methods is commonly used to evade 802.1X authentication?

Accepted Answer

MAC address spoofing. MAC address spoofing is a common way to bypass Network Access Control (NAC) when the system relies on MAC-based authentication or port security, such as MAC Authentication Bypass (MAB) or MAC filtering. Although standard 802.1X uses EAP, not MAC address, for authentication, many NAC implementations combine 802.1X with MAC-based fallbacks. By spoofing the MAC address of an already-approved device, an attacker can impersonate it and gain network access without valid credentials. Additionally, after a device authenticates via 802.1X, the switch may bind the port to that MAC address; spoofing that MAC would allow an attacker to reuse the port.

Answer

VLAN hopping using double tagging

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DNS tunneling to exfiltrate data

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ARP poisoning to redirect traffic

Question 3

A security team needs to preserve network evidence for a potential legal case. What is the BEST practice for capturing volatile network data?

Accepted Answer

Perform packet capture using a portable tool and store the capture with a cryptographic hash. Capturing volatile network data requires immediate acquisition of live traffic before it is lost, and using a portable tool (e.g., tcpdump, Wireshark) allows rapid deployment. Storing the capture with a cryptographic hash (e.g., SHA-256) ensures data integrity and chain of custody, which is essential for admissibility in legal proceedings. This approach preserves the most volatile evidence (packet contents) while providing verifiable proof that the data has not been altered.

Answer

Wait until normal business hours to capture traffic

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Only record summary logs from the firewall

Answer

Use a dedicated forensic workstation with a write blocker

Question 4

In a cloud forensic investigation, the analyst needs to obtain a memory dump of a virtual machine. Which method is considered forensically sound?

Accepted Answer

Take a snapshot of the VM via the hypervisor and export the .vmem file. Forensically sound because taking a snapshot of the VM via the hypervisor and exporting the .vmem file captures the entire volatile memory state from outside the guest OS, without altering any data inside the VM. This method preserves the memory in its pristine state and avoids the contamination that occurs when executing tools inside the suspect VM.

Answer

Log into the VM and use a tool to create a crash dump

Answer

Copy the virtual disk file (.vmdk) and extract memory from it

Answer

Use a live forensic tool inside the VM to capture memory

Question 5

An organization uses a cloud-based SIEM to collect logs from multiple sources. The investigator notices gaps in the log data for a critical system during the incident timeframe. What is the MOST likely cause?

Accepted Answer

Time drift between the system and the SIEM. Time drift between the system and the SIEM causes logs to be timestamped incorrectly, leading to apparent gaps when the SIEM queries by time range. Even if logs are delivered, they may fall outside the incident timeframe in the SIEM's index, creating the illusion of missing data. This is a common issue in cloud-based SIEMs where NTP synchronization is not enforced across all sources.

Answer

Network latency delayed log delivery

Answer

Log rotation policy deleted logs prematurely

Answer

The system's log level was set to ERROR only

Question 6

During a network forensic investigation, the analyst recovers a PCAP file. What type of information can be directly extracted from this file?

Accepted Answer

Files transferred via HTTP. A PCAP file captures raw network packets. HTTP is an application-layer protocol that transmits data (e.g., files, web pages) in cleartext over TCP. By reassembling TCP streams from the captured packets, an analyst can directly extract files transferred via HTTP, as the payload contains the actual file content.

Answer

Operating system version of the source host

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Registry data of the destination host

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Disk partition table of the sending computer

Question 7

An investigator is analyzing cloud storage logs and finds an entry showing that a file was accessed using the root credentials from an IP address in a different geographic region. The organization has strict policies against root usage. What should the investigator do FIRST?

Accepted Answer

Check if the activity correlates with a known vulnerability or authorized task. The first step in any forensic investigation is to correlate the suspicious activity with known events, such as authorized tasks or vulnerabilities, to avoid false positives. Root access from an unfamiliar IP could be legitimate if tied to a scheduled maintenance window or a known vulnerability exploitation attempt that requires verification. Prematurely changing credentials or contacting law enforcement could destroy evidence or alert an attacker before the scope is understood.

Answer

Contact law enforcement for cybercrime investigation

Answer

Change the password of the root account

Answer

Immediately revoke the root access keys

Question 8

A forensic analyst is examining a network intrusion detection system (NIDS) alert that triggered on a packet with the FIN, PSH, and URG flags set. What type of scan does this indicate?

Accepted Answer

Xmas scan. A is correct because an Xmas scan sends packets with the FIN, PSH, and URG flags set (like a Christmas tree lit up). According to RFC 793, a closed port must respond with an RST packet, while an open port should drop the packet silently (no response). The NIDS alert triggered on these three flags together, which is the signature of an Xmas scan.

Answer

NULL scan

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SYN scan

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ACK scan

Question 9

Which TWO of the following are common challenges in cloud forensics?

Accepted Answer

Jurisdictional and legal issues due to data stored in multiple regions. Cloud forensic investigations often involve data stored across multiple geographic regions, each with its own data protection laws (e.g., GDPR, CLOUD Act). This creates jurisdictional conflicts regarding lawful access, data privacy, and chain of custody, which are not present in traditional on-premises forensics.

Answer

All cloud environments provide the same forensic capabilities

Answer

Easier evidence acquisition compared to traditional forensics

Answer

Physical access to the hard drive is always available

Question 10

Which THREE of the following are essential steps in network forensic investigation?

Accepted Answer

Create a timeline of network events. Creating a timeline of network events (Option B) is essential in network forensic investigation because it establishes a sequence of activities, correlating packet captures, logs, and system events to reconstruct the attack path. This chronological mapping is critical for identifying the initial compromise point, lateral movement, and data exfiltration, often using tools like Wireshark or tcpdump with timestamps from NTP-synchronized sources.

Answer

Conduct interviews with all network users

Answer

Perform a bit-for-bit copy of all hard drives

Question 11

Which TWO of the following are effective methods for detecting a man-in-the-middle attack on a network?

Accepted Answer

Check for SSL certificate mismatches. SSL certificate mismatches occur when a man-in-the-middle (MITM) attacker presents a forged or self-signed certificate that does not match the legitimate server's certificate. Browsers and security tools will flag this mismatch (e.g., different Common Name, invalid issuer, or expired validity), providing a clear indicator of an ongoing MITM attack. Monitoring for ARP cache poisoning is also an effective detection method because MITM attackers often use ARP spoofing to intercept network traffic. By detecting anomalies in ARP tables (e.g., duplicate IP addresses with different MAC addresses), security tools can identify an ongoing MITM attack on the local network.

Answer

Analyze DNS amplification traffic

Answer

Implement port knocking for access control

Answer

Detect ICMP flood attacks

Question 12

Based on the ARP table exhibit, what is the most likely security issue?

Accepted Answer

ARP poisoning attack. The ARP table exhibit shows a single IP address (192.168.1.1) mapped to two different MAC addresses (00:11:22:33:44:55 and AA:BB:CC:DD:EE:FF). This is a classic indicator of an ARP poisoning attack, where an attacker sends forged ARP replies to associate their MAC address with the gateway's IP, enabling man-in-the-middle interception of traffic.

Answer

The gateway is unreachable

Answer

Duplicate IP addresses on the network

Answer

MAC address filtering is enabled

Question 13

An investigator finds the above IAM policy attached to an S3 bucket. What is the security concern?

Accepted Answer

The bucket is publicly accessible to read objects. The IAM policy's `Principal` is set to `"*"` (wildcard), which means any unauthenticated user or anonymous entity on the internet can perform the `s3:GetObject` action. This makes the S3 bucket publicly readable, exposing all objects stored in the bucket to anyone who knows the bucket name and object key. The `Effect` is `Allow` and there is no condition restricting access, so the policy grants open read access to the entire bucket.

Answer

The resource does not include all objects

Answer

The policy version is outdated

Answer

The policy allows anyone to write objects to the bucket

Question 14

Based on the log exhibit, what type of attack is occurring?

Accepted Answer

Brute-force attack on SSH. The log shows multiple failed SSH login attempts from the same IP address with different usernames and passwords, which is characteristic of a brute-force attack targeting SSH. The repeated 'Failed password' entries for various user accounts (e.g., root, admin, user) indicate an automated attempt to guess credentials, not a single successful compromise or a different attack type.

Answer

Man-in-the-middle attack

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SQL injection attack

Answer

Denial of Service attack

Question 15

You are a forensic investigator for a healthcare organization that uses a hybrid cloud model. Your team receives an alert that a large amount of protected health information (PHI) was exfiltrated from an AWS S3 bucket to an external IP address. The organization uses AWS CloudTrail for API logging and VPC Flow Logs for network traffic. The incident occurred between 02:00 and 03:00 UTC. Upon reviewing CloudTrail logs, you see that the bucket policy was modified at 01:55 UTC to allow public read access, and then a series of GetObject requests from an IP address in a foreign country occurred. The VPC Flow Logs show outbound traffic from the bucket's VPC to that IP. The bucket policy change was made using the root user credentials of the AWS account. The organization has multi-factor authentication (MFA) enabled for all users, including root. However, the CloudTrail log for the policy change does not indicate MFA usage. You need to determine the most likely root cause of the breach. Which of the following is the most plausible explanation?

Accepted Answer

The root user's credentials were compromised and used to modify the bucket policy. The root user credentials were likely compromised because the CloudTrail log for the bucket policy change at 01:55 UTC shows no MFA usage, despite MFA being enforced for all users including root. This indicates the attacker used stolen root access keys or password without the MFA token, which is a common attack vector when credentials are phished or leaked. The subsequent GetObject requests from a foreign IP and outbound VPC Flow Logs confirm the exfiltration path.

Answer

The bucket policy was automatically modified by an AWS service

Answer

An insider with IAM permissions made the change using a legitimate session

Answer

The CloudTrail logs are inaccurate and the policy change was not made

Question 16

You are investigating a network breach at a financial institution. The organization uses a network-based intrusion detection system (NIDS) and maintains full packet capture (PCAP) for critical segments. The incident allegedly started with a spear-phishing email that delivered a remote access trojan (RAT). The security team has isolated the infected host and provided you with a disk image of the host and a PCAP file covering the network traffic from the host for the 24-hour period before isolation. In the PCAP, you see a series of TCP connections from the host to an external IP address on port 443 (HTTPS). The external IP is known to be associated with a command-and-control (C2) server. However, the disk image shows no evidence of the RAT binary or any malicious files. The host's antivirus logs are clean. Which of the following is the most likely explanation for the lack of evidence on the disk?

Accepted Answer

The malware was fileless and only resided in memory. The absence of the RAT binary and any malicious files on the disk, combined with clean antivirus logs and active C2 traffic over HTTPS, strongly indicates a fileless malware infection. Fileless malware operates entirely in memory (RAM), never writing its payload to disk, which explains why the disk image shows no artifacts and why traditional file-scanning antivirus did not detect it. The TCP connections to the C2 server on port 443 are consistent with a memory-resident RAT that loads directly into a legitimate process (e.g., PowerShell, WMI, or a script interpreter) and communicates over encrypted HTTPS to evade network inspection.

Answer

The antivirus software deleted the malicious files before the image was taken

Answer

The hard drive was reimaged before the forensic image was taken

Answer

The RAT uses a rootkit to hide its files

Question 17

During a forensic investigation of a cloud environment, a forensic analyst discovers that the virtual machine (VM) used by a suspect was terminated three days prior. The cloud provider offers snapshots, backups, and instance metadata. Which of the following is the BEST course of action to recover forensic evidence?

Accepted Answer

Restore the VM from a recent snapshot or backup provided by the cloud provider.. Once a VM is terminated, its underlying instance store or ephemeral disks are destroyed, but persistent snapshots and backups retain the disk state at the time they were taken. Restoring from a recent snapshot or backup is the only reliable method to recover the VM's file system, application data, and user artifacts for forensic analysis in a cloud environment.

Answer

Examine CloudTrail logs for disk contents.

Answer

Access the VM’s operating system via the cloud console’s serial console.

Answer

Use SSH credentials from the investigation to connect to the terminated instance.

Question 18

A forensic investigator needs to capture network traffic from a SPAN port on a switch to analyze an ongoing compromise. Which tool should the investigator use to collect the full packet capture (pcap) for later analysis?

Accepted Answer

tcpdump. tcpdump is a command-line packet capture utility that captures raw network traffic at the link layer, making it ideal for collecting full packet captures (PCAP) from a SPAN port. Unlike GUI tools, it can run headless on a forensic workstation and write binary PCAP files for later analysis with tools like Wireshark. It captures all packets traversing the SPAN port without filtering by default, ensuring a complete record of the compromise.

Answer

NetFlow

Answer

nmap

Answer

Wireshark

Question 19

A cloud forensic analyst is tasked with preserving evidence from an AWS S3 bucket that may contain malicious files. The bucket is publicly accessible, and the analyst wants to create a forensically sound copy. Which method BEST ensures integrity and chain of custody?

Accepted Answer

Use the AWS CLI sync command with the --checksum-mode flag to verify integrity during transfer.. The AWS CLI `sync` command with the `--checksum-mode` flag automatically computes and compares checksums (e.g., SHA256) during the transfer, ensuring data integrity without manual intervention. This method also preserves metadata and timestamps, which is critical for maintaining a forensically sound copy and chain of custody in cloud forensics.

Answer

Download each object via the AWS Management Console and compute SHA256 hashes manually.

Answer

Use the AWS CLI cp command recursively without any flags.

Answer

Generate a presigned URL for the bucket and use wget to download all files.

Question 20

Which TWO of the following are valid techniques for collecting volatile network evidence from a live system during incident response?

Accepted Answer

Running netstat -an to view active TCP/UDP connections.. `netstat -an` displays all active TCP and UDP connections along with their listening ports and states, which is critical for identifying unauthorized or malicious network connections on a live system. This command provides a snapshot of current network sessions without altering system state, making it a standard volatile evidence collection technique.

Answer

Using route print to view the IP routing table.

Answer

Using ipconfig /displaydns to view the DNS resolver cache.

Answer

Running arp -a to view the ARP table.