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CCNA Iot And OT Exploitation Questions

57 questions · Iot And OT Exploitation · All types, answers revealed

1
Multi-Selectmedium

A hardware penetration tester is investigating an IoT device printed circuit board (PCB) to extract sensitive firmware or debug data. Which THREE of the following physical hardware interfaces are commonly targeted by testers to gain console access or read memory? (Choose THREE)

Select 3 answers
A.HDMI display output pins used for high-speed video graphics rendering
B.RJ-45 Ethernet port pin 8 carrying PoE (Power over Ethernet) voltage directly to the CPU core
C.SPI (Serial Peripheral Interface) flash memory pins
D.UART (Universal Asynchronous Receiver-Transmitter)
E.JTAG (Joint Test Action Group)
AnswersC, D, E

SPI flash chips store bootloaders, kernels, and file systems, and can be read using clip-on programmers.

Why this answer

Physical hardware hacking heavily relies on serial debug interfaces like UART, JTAG for boundary-scan debugging, and SPI/I2C for flash memory extraction.

2
MCQmedium

A security analyst is investigating an IoT incident where an attacker gained unauthorized access to an MQTT broker. The analyst wants to inspect the broker configuration file on a Debian-based Linux system running Eclipse Mosquitto to check if anonymous access was enabled. What is the default file path for the Mosquitto configuration file?

A./etc/mosquitto/mosquitto.conf
B./var/lib/mqtt/config.ini
C./opt/broker/settings.xml
D./etc/init.d/mosquitto.cfg
AnswerA

The Mosquitto configuration file is located at '/etc/mosquitto/mosquitto.conf', where parameters like 'allow_anonymous' are defined.

Why this answer

Eclipse Mosquitto stores its primary configuration settings in '/etc/mosquitto/mosquitto.conf' on standard Linux installations.

3
MCQmedium

An ethical hacker is testing an ICS network that utilizes the IEC 60870-5-104 protocol for telecontrol equipment. The hacker wants to test whether control commands can be sent without proper authentication. Which Wireshark filter syntax should the hacker apply to isolate IEC 104 application layer frames in a capture file?

A.s7comm
B.mms
C.iec104
D.bacnet
AnswerC

The 'iec104' filter isolates IEC 60870-5-104 application layer traffic in Wireshark.

Why this answer

IEC 60870-5-104 operates over TCP port 2404. Wireshark decodes this under the 'iec104' protocol filter.

4
MCQhard

An ICS penetration tester is auditing a substation utilizing the IEC 61850 standard for electrical substation automation. The tester captures Generic Object Oriented Substation Events (GOOSE) messages on the network. Which Layer 2 Ethernet type hex value identifies GOOSE multicast frames?

A.0x0800
B.0x86DD
C.0x88B8
D.0x88E5
AnswerC

IEC 61850 GOOSE protocol frames use EtherType 0x88B8 for high-speed Layer 2 multicast communications.

Why this answer

GOOSE messages in IEC 61850 bypass the IP/TCP stack for speed and operate directly at Layer 2 using EtherType 0x88B8.

5
MCQeasy

A penetration tester is analyzing a smart medical pump and needs to check for open ports and running services on the embedded operating system. Using Nmap, the tester wants to perform a TCP SYN scan against the device while avoiding noisy service version detection to remain stealthy. Which Nmap flag specifies a SYN stealth scan?

A.-sT
B.-sP
C.-sS
D.-sU
AnswerC

The '-sS' option triggers a TCP SYN scan, sending SYN packets and analyzing responses without establishing full TCP connections.

Why this answer

The '-sS' flag instructs Nmap to perform a TCP SYN scan, which is the default and most popular stealth scan because it never completes the full 3-way handshake.

6
Multi-Selecthard

An IoT firmware analyst is performing emulation of a MIPS-based router firmware binary using Firmadyne. Which TWO of the following steps or components are critical to successfully emulate and analyze the firmware image? (Choose TWO)

Select 2 answers
A.Brute-forcing SSH passwords using Hydra against the host machine
B.Populating a PostgreSQL database with image metadata and utilizing Firmadyne helper scripts to extract the file system
C.Executing an SQL injection payload against the web server running on port 80
D.Sniffing 802.11 wireless beacons with an external USB Wi-Fi adapter in monitor mode
E.Running the emulated kernel image within QEMU system mode (e.g., qemu-system-mips) using a patched initrd
AnswersB, E

Firmadyne relies heavily on a PostgreSQL database backend to track image configurations, network interfaces, and extraction results.

Why this answer

Firmadyne emulation requires extracting the file system, initializing a PostgreSQL database to store image metadata, and running specialized QEMU system emulators with a modified kernel.

7
MCQmedium

A pentester is analyzing an industrial control network and identifies devices communicating via EtherNet/IP (CIP). The pentester wants to enumerate explicit messaging objects and device identity data. Which Nmap script should the tester invoke?

A.modbus-discover
B.enip-info
C.bacnet-discover
D.dnp3-info
AnswerB

The 'enip-info' script queries port 44818 and extracts Common Industrial Protocol (CIP) identity object attributes.

Why this answer

Nmap includes the 'enip-info' NSE script specifically designed to query EtherNet/IP devices for identification and vendor details.

8
MCQmedium

An assessment team is analyzing an embedded Linux firmware image for an industrial IoT gateway. They have successfully extracted the filesystem using Binwalk, but they need to statically analyze the compiled binaries for potential buffer overflows and insecure function calls. Which tool is specifically designed to perform static binary analysis and identify vulnerable functions likestrcpy within the extracted filesystem?

A.Aircrack-ng
B.Binwalk
C.Ghidra
D.John the Ripper
AnswerC

Ghidra is a software reverse engineering framework developed by the NSA that performs static analysis to find vulnerable functions in binaries.

Why this answer

Checksec or a tool like IDA Pro / Ghidra can analyze binaries, but Ghidra or Radare2 are specifically suited for deep reverse engineering and identifying insecure function imports within extracted firmware binaries. Binwalk extracts files, aircrack-ng is for Wi-Fi, and John the Ripper is for password cracking.

9
MCQeasy

A penetration tester is analyzing an IoT mobile companion app that communicates with a smart thermostat via BLE (Bluetooth Low Energy). Which tool can the tester use on a rooted Android device to intercept and inspect BLE GATT characteristics and descriptors?

A.Hydra
B.Sqlmap
C.Aircrack-ng
D.nRF Connect for Mobile
AnswerD

nRF Connect allows testers to scan, read, write, and subscribe to BLE GATT characteristics and descriptors on Android and iOS.

Why this answer

GATT Explorer or specialized dynamic instrumentation frameworks like Frida or BLE sniffing tools on Android are used, but specifically for intercepting and manipulating BLE traffic locally on the device, 'GATTacker' or apps like 'nRF Connect' / 'Frida scripts' are deployed. Among standard choices, nRF Connect is the industry-standard diagnostic and testing tool for BLE.

10
MCQhard

During an IoT penetration test, an analyst discovers that a connected medical device communicates with its cloud backend using MQTT over TLS, but certificate validation is disabled in the client code. The analyst wants to perform a man-in-the-middle (MitM) attack to inspect the MQTT traffic. Which tool configured with a custom Certificate Authority (CA) is best suited to intercept this TLS-wrapped MQTT traffic?

A.mitmproxy
B.Airodump-ng
C.Ncat
D.Hping3
AnswerA

mitmproxy is an interactive TLS-capable man-in-the-middle proxy that supports TCP stream interception, allowing decryption and inspection of MQTT-over-TLS.

Why this answer

Burp Suite or mitmproxy can act as transparent or explicit proxies, terminating the TLS connection using a rogue CA certificate, allowing inspection and modification of MQTT-over-TLS traffic.

11
MCQeasy

During an IoT assessment, a tester discovers that a connected security camera runs an embedded web server with a CGI script vulnerable to OS command injection via a GET parameter. Which automated vulnerability scanner includes specific modules for detecting web-based CGI vulnerabilities and command injection?

A.Reaver
B.Masscan
C.Nikto
D.Aircrack-ng
AnswerC

Nikto scans web servers against a comprehensive database of over 6,700 potentially dangerous files, outdated server versions, and vulnerable CGI scripts.

Why this answer

Nikto is a comprehensive web server scanner that checks for dangerous files, outdated software, and CGI scripts, while Metasploit contains specific modules for exploitation.

12
Multi-Selectmedium

An OT security analyst is reviewing network traffic on an industrial control system network and identifies DNP3 protocol packets. Which THREE of the following fields or functions are associated with the DNP3 protocol structure and security? (Choose THREE)

Select 3 answers
A.Application layer function codes specifying operations like Read, Write, Select, and Operate
B.IEEE 802.11 WPA2 four-way handshake cryptographic parameters
C.Data link layer CRC error detection checksums embedded in data blocks
D.HTTP Authorization Bearer tokens used for REST API authentication
E.DNP3 Secure Authentication (SA) extensions designed to prevent unauthorized command injection and spoofing
AnswersA, C, E

DNP3 utilizes function codes (e.g., Read=1, Write=2, Select=3, Operate=4) to manage station data and control relays.

Why this answer

DNP3 features application layer functions, object headers, and Secure Authentication extensions (IEC 62351-5) to prevent spoofing of control commands.

13
MCQhard

A security researcher is evaluating an industrial IoT gateway running Linux. During a filesystem audit of the extracted rootfs, the researcher finds that the '/etc/shadow' file contains weak password hashes for the root user. Which utility can the researcher use offline on their host machine to attempt password cracking via dictionary attack against the extracted hash?

A.Binwalk
B.John the Ripper
C.Nmap
D.Tcpdump
AnswerB

John the Ripper supports a wide variety of Unix crypt hash formats found in '/etc/shadow' for offline password recovery.

Why this answer

John the Ripper and Hashcat are industry-standard password cracking tools that accept shadow file formats for offline dictionary and brute-force attacks.

14
Multi-Selecthard

During an assessment of a smart manufacturing facility, a penetration tester discovers an unauthenticated MQTT broker allowing anonymous publishing and subscription. Which TWO actions should the tester perform to validate the security risks associated with this misconfiguration? (Choose TWO)

Select 2 answers
A.Perform an aggressive TCP port scan using Nmap to identify non-standard service ports
B.Publish arbitrary control messages to actuator topics to test if physical machinery responds to unauthorized commands
C.Capture WPA2 four-way handshakes to crack the underlying Wi-Fi pre-shared key
D.Execute a brute-force dictionary attack against the MQTT broker management interface using Hydra
E.Subscribe to the root topic using the wildcard character '#' to capture all telemetry and potentially sensitive messages
AnswersB, E

Publishing to control topics validates whether the broker enforces authorization controls for critical OT commands.

Why this answer

An unauthenticated MQTT broker allows anyone to subscribe to all topics (# wildcard) to intercept sensitive telemetry, or publish malicious commands to actuator topics. Therefore, subscribing to all topics and testing command injection via unauthorized publishing are the correct validation steps. Port scanning and password cracking are unnecessary when authentication is already known to be absent.

15
Multi-Selecthard

A security consultant is performing a penetration test against an embedded IoT device that exposes an insecure bootloader and serial console. Which TWO of the following procedures can the consultant execute via the U-Boot serial prompt to compromise device security? (Choose TWO)

Select 2 answers
A.Cracking WPA2 Pre-Shared Keys using a dictionary attack and Aircrack-ng
B.Executing an ARP spoofing attack to intercept printer traffic on the corporate IT network
C.Injecting an SQL injection payload into the device's Bluetooth GATT profile characteristic
D.Using TFTP to load and execute an unauthorized custom kernel image into device RAM
E.Interrupting the boot countdown and modifying 'bootargs' to append 'init=/bin/sh' to spawn a root shell
AnswersD, E

U-Boot supports network commands like tftpboot to load and run arbitrary kernel images over the network.

Why this answer

Via the U-Boot serial prompt, an attacker can interrupt the boot sequence, override kernel command line arguments (e.g., init=/bin/sh), or boot a custom kernel image via TFTP.

16
MCQeasy

An ethical hacker is examining an operational technology (OT) network and needs to identify programmable logic controllers (PLCs) using their native industrial protocols. Which default TCP port should the hacker scan to discover Modbus/TCP devices?

A.TCP 102
B.TCP 20000
C.TCP 502
D.UDP 44818
AnswerC

Port 502 is the official registered TCP port for Modbus communications.

Why this answer

Modbus/TCP is an open protocol widely used in SCADA environments and operates natively over TCP port 502.

17
MCQmedium

A penetration tester is reviewing the firmware of a smart electricity meter and discovers that the bootloader is unlocked. The tester connects a USB-to-UART serial adapter to the board's exposed pins and interrupts the boot sequence to gain a root shell. Which environment variable or kernel boot parameter must the tester modify to bypass the root password authentication prompt entirely?

A.rootfstype=squashfs
B.ip=DHCP
C.mem=256M
D.init=/bin/sh
AnswerD

Passing init=/bin/sh to the kernel command line overrides the default init process and drops the user directly into an unauthenticated root shell.

Why this answer

Appending 'init=/bin/sh' or 'init=/bin/bash' to the kernel boot arguments (bootargs) forces the Linux kernel to spawn a shell directly upon booting, bypassing init scripts and authentication prompts. 'rootfstype' defines the filesystem type, 'ip=' configures networking, and 'mem=' limits RAM.

18
Multi-Selectmedium

A security engineer is hardening an industrial SCADA environment against remote attacks. Which THREE of the following mitigation strategies are recommended best practices for securing OT networks? (Choose THREE)

Select 3 answers
A.Deploying industrial Intrusion Detection Systems (IDS) capable of parsing proprietary OT protocols (e.g., Modbus, DNP3, S7)
B.Utilizing unidirectional security gateways (data diodes) where data must flow from OT to IT without permitting inbound return paths
C.Allowing unrestricted direct Internet access from all PLC controllers for automated driver updates
D.Disabling all encryption across SCADA servers to improve packet inspection speeds on firewalls
E.Implementing strict network segmentation between IT corporate networks and OT plant floors using firewalls
AnswersA, B, E

Industrial IDS solutions monitor for anomalous command sequences and unauthorized protocol operations on the control network.

Why this answer

Securing OT networks involves strict Purdue model network segmentation, deploying unidirectional security gateways (data diodes), and implementing industrial IDS solutions.

19
MCQmedium

An OT security engineer is conducting a vulnerability assessment on a Distributed Control System (DCS). The engineer needs to test for unauthorized firmware write capabilities on a legacy controller using the Modbus protocol. Which Modbus function code is typically associated with writing multiple holding registers, which could be abused to modify configuration parameters?

A.Function Code 01 (0x01) - Read Coils
B.Function Code 04 (0x04) - Read Input Registers
C.Function Code 02 (0x02) - Read Discrete Inputs
D.Function Code 16 (0x10) - Write Multiple Registers
AnswerD

Function Code 0x10 allows writing blocks of holding registers, which often control setpoints, operational parameters, and logic variables.

Why this answer

Modbus function codes define the action to be performed. Function Code 16 (0x10) is 'Write Multiple Registers', frequently used to change register blocks in industrial controllers.

20
MCQmedium

An analyst is examining the firmware of an IoT gateway and discovers a JFFS2 file system image. The analyst wants to extract the file system contents. Which tool, specifically designed for JFFS2 extraction and analysis, should the analyst run on a Linux workstation?

A.dpkg-deb
B.jeffs2dump / mtd-utils
C.rpmbuild
D.apt-get extract
AnswerB

Utilities within mtd-utils such as jeffs2dump allow parsing and extracting JFFS2 compressed flash image formats.

Why this answer

The 'mtd-utils' package includes tools like 'jeffs2dump' and 'nanddump', while 'jeffs2dump' or 'jeffs2extract' utilities unpack JFFS2 file systems.

21
MCQmedium

An auditor is reviewing an ICS network architecture and notes that a Supervisory Control and Data Acquisition (SCADA) server communicates with remote terminal units (RTUs) via DNP3 over serial-to-ethernet terminal servers. The auditor wants to test if unauthenticated DNP3 control commands can be accepted. Which default port should the auditor probe for DNP3 traffic?

A.TCP 443
B.TCP 2404
C.TCP/UDP 20000
D.TCP 44818
AnswerC

Port 20000 is the standard port assigned for DNP3 communications in industrial networks.

Why this answer

DNP3 (Distributed Network Protocol) is heavily used in electric and water utilities and operates by default on TCP/UDP port 20000.

22
MCQeasy

During an assessment of a smart water treatment facility, an analyst notices an HTTP-based web interface running on an embedded PLC. The analyst wants to discover hidden administrative backup directories and configuration files on the web server. Which command-line tool is specifically designed for brute-forcing web server directories and files?

A.Gobuster
B.Wifite
C.Nbtscan
D.Hping3
AnswerA

Gobuster is a fast tool written in Go used to brute-force URIs, directories, and DNS subdomains on web servers.

Why this answer

Gobuster or Dirb/Dirbuster are standard directory brute-forcing tools used to find hidden web resources.

23
MCQhard

An engineer is conducting a security audit on a smart grid device that uses CoAP over DTLS. The engineer attempts to intercept the handshake and notices pre-shared key (PSK) cipher suites are enabled. Which OpenSSL command can the engineer use to test connecting to the DTLS service using a specific Pre-Shared Key identifier and hex-encoded key?

A.openssl s_client -dtls1 -psk 01020304 -psk_identity test_id -connect 192.168.1.50:5684
B.ssh -p 5684 -o KexAlgorithms=psk 192.168.1.50
C.nc -u 192.168.1.50 5684
D.telnet 192.168.1.50 5684
AnswerA

The openssl s_client command supports '-dtls1', '-psk', and '-psk_identity' to authenticate against DTLS-PSK protected endpoints.

Why this answer

OpenSSL supports DTLS testing and allows specifying PSK identity and keys using parameters like '-psk' and '-psk_identity'.

24
Multi-Selecthard

An IoT penetration tester is analyzing the security of a Zigbee smart lighting installation. Which TWO of the following tools or frameworks are specifically utilized when assessing 802.15.4 and Zigbee wireless security? (Choose TWO)

Select 2 answers
A.KillerBee (Python framework for exploiting Zigbee/IEEE 802.15.4)
B.Aircrack-ng suite for cracking WPA-PSK Wi-Fi pre-shared keys
C.Wireshark configured with a captured network key to decrypt 802.15.4 application layers
D.Metasploit 'msfvenom' module generating Windows Meterpreter payloads for Active Directory persistence
E.Burp Suite Professional for intercepting HTTP requests from web applications
AnswersA, C

KillerBee provides tools for packet sniffing, node enumeration, and packet injection against Zigbee networks.

Why this answer

KillerBee and Universal Radio Hacker (URH) or Wireshark with appropriate hardware dongles (like CC2531) are standard toolsets for Zigbee and 802.15.4 assessments.

25
Multi-Selectmedium

A penetration tester is conducting an assessment of an MQTT-based smart home ecosystem. Which THREE of the following security configuration checks should the tester perform on the MQTT broker? (Choose THREE)

Select 3 answers
A.Verifying that the broker responds to Modbus/TCP function code 0x10 write requests
B.Testing if Access Control Lists (ACLs) are enforced to restrict topic publishing and subscribing rights
C.Executing an 802.11 deauthentication flood against the MQTT broker's MAC address
D.Verifying whether anonymous client connections are permitted by the broker
E.Checking if communication traffic is encrypted using TLS (Transport Layer Security)
AnswersB, D, E

Without ACLs, any authenticated client can access and control sensitive command topics across the broker.

Why this answer

MQTT security assessments focus heavily on authentication, authorization (ACLs), and transport encryption (TLS).

26
MCQeasy

A penetration tester is evaluating a smart home IoT hub and needs to extract the firmware to analyze hardcoded cryptographic keys. The device exposes a physical debugging interface on the board with clock, data, ground, and power pins. Which hardware hacking tool should the tester connect to these pins to interact with the internal flash memory and dump the firmware?

A.Bus Pirate
B.Wireshark
C.Logic Analyzer
D.HackRF One
AnswerA

The Bus Pirate is a universal bus interface that can communicate over SPI and I2C to read flash memory chips directly.

Why this answer

A Bus Pirate or similar hardware interface tool (like a Shikra or Total Phase Beagle) is used to interact with hardware communication protocols such as SPI, I2C, and UART to dump firmware. Wireshark is a network protocol analyzer, HackRF One is a software-defined radio for wireless analysis, and a Logic Analyzer captures signals but does not actively interface for reading/writing flash memory in this context.

27
MCQeasy

A penetration tester is evaluating an embedded IoT device that exposes a Telnet service on port 23. The tester suspects default credentials are in use. Which command-line tool can the tester use to perform a fast dictionary attack against the Telnet service using a username and password list?

A.Sqlmap
B.Hydra
C.Nikto
D.Wpscan
AnswerB

Hydra supports brute-forcing Telnet authentication with specified user and password lists.

Why this answer

Hydra is a versatile, parallelized login cracker supporting numerous network authentication protocols, including Telnet.

28
Multi-Selecthard

An ethical hacker is evaluating a Bluetooth Low Energy (BLE) medical sensor. Which TWO of the following vulnerabilities or attack vectors are commonly associated with insecure BLE implementations in IoT devices? (Choose TWO)

Select 2 answers
A.Executing a remote buffer overflow against the Linux kernel via wireless 802.11 management frames
B.Static or hardcoded pairing PINs (e.g., '0000' or '1234') susceptible to sniffing and brute-forcing
C.Injecting malicious SQL statements into the BLE radio frequency advertising packets
D.Performing an ARP cache poisoning attack against the target device's switch port
E.Insecure GATT characteristics allowing unauthorized unauthenticated read and write operations
AnswersB, E

Using static or weak pairing PINs allows attackers to sniff pairing exchanges or brute-force the PIN to establish an encrypted connection.

Why this answer

BLE implementations frequently suffer from lack of encryption/pairing authentication, insecure GATT characteristic permissions allowing arbitrary reads/writes, and predictable static pairing PINs.

29
MCQmedium

An ethical hacker is performing a security assessment on an industrial facility and discovers an open Zigbee network. The hacker wants to perform active reconnaissance to map all connected nodes and routing tables. Which open-source toolset provides utilities like 'zigbee-discovery' and packet generation for IEEE 802.15.4 networks?

A.Impacket
B.Airgeddon
C.Bettercap
D.KillerBee
AnswerD

KillerBee provides tools like zbdump, zbgoodfind, and zigbee-discovery to assess the security of Zigbee implementations.

Why this answer

KillerBee is a popular Python framework and toolset for security auditing and exploiting Zigbee and IEEE 802.15.4 networks.

30
Multi-Selectmedium

An IoT penetration tester is conducting a security audit of a Linux-based smart gateway. Which THREE of the following commands or file inspection techniques can the tester use on the device (or extracted rootfs) to identify privilege escalation vectors or misconfigurations? (Choose THREE)

Select 3 answers
A.Analyzing Modbus holding registers for unauthorized register modifications
B.Checking Bluetooth GATT profile characteristics using nRF Connect
C.Reviewing sudo privileges using 'sudo -l'
D.Inspecting scheduled tasks and cron jobs in '/etc/crontab' and '/var/spool/cron/'
E.Finding files with SUID/SGID permissions using 'find / -perm -4000 2>/dev/null'
AnswersC, D, E

The 'sudo -l' command lists permitted sudo commands for the current user, revealing if they can run administrative commands without a password.

Why this answer

Finding privilege escalation vectors involves searching for SUID/SGID binaries, inspecting sudo permissions, and checking cron jobs.

31
Multi-Selecthard

An ICS penetration tester is auditing a manufacturing plant floor. Which TWO of the following methodologies or tools are specifically used for identifying and fingerprinting industrial control system devices across the network? (Choose TWO)

Select 2 answers
A.Using 'Aircrack-ng' to inject Bluetooth Low Energy advertisements into nearby smart meters
B.Running 'sqlmap' against TCP port 80 to extract database schemas from the corporate ERP
C.Cracking WPA2 enterprise handshakes using Hashcat and a dictionary list
D.Using Nmap with industrial NSE scripts such as 'modbus-discover', 's7-info', and 'enip-info'
E.Employing active asset discovery tools designed for OT environments (e.g., Nozomi Guardian, Claroty, or Dragos Platform)
AnswersD, E

Nmap ICS scripts query specific OT ports to safely extract model numbers, firmware versions, and rack/slot data.

Why this answer

Fingerprinting ICS equipment involves using Nmap NSE scripts tailored for industrial protocols or specialized asset discovery tools like Shodan/Industrial Defender tools.

32
MCQmedium

An IoT penetration tester successfully dumps the flash memory of an embedded router. The resulting binary image contains a U-Boot bootloader environment. Which command can the tester look for or attempt to inject via the serial console to override the Linux kernel boot arguments and spawn a root shell?

A.tftp 0x80000000 kernel.bin
B.printenv mtdparts
C.setenv bootargs ${bootargs} init=/bin/sh
D.run flash_os_image
AnswerC

Modifying the 'bootargs' environment variable in U-Boot to include 'init=/bin/sh' bypasses standard authentication and provides a direct root shell upon boot.

Why this answer

U-Boot uses environment variables to define boot parameters. Appending 'init=/bin/sh' or 'init=/bin/bash' to the 'bootargs' variable forces the kernel to launch a shell instead of the standard init process.

33
MCQhard

A penetration tester is assessing an MQTT-based industrial monitoring system where brokers communicate over unencrypted TCP ports. The tester wants to discover hidden topics that are not actively publishing data by brute-forcing topic names. Which tool natively supports MQTT fuzzing and topic discovery through automated subscription testing?

A.MQTT-Miner
B.DirBuster
C.Nmap
D.Nikto
AnswerA

MQTT-Miner is an OWASP tool integrated with Burp Suite designed specifically to discover MQTT topics and test broker security.

Why this answer

MQTT-Miner or specialized tools like the MQTTSA (MQTT Security Assessment) framework or Metasploit modules are used. Specifically, MQTT-Miner is designed for testing and discovering topics. Nmap performs port scanning, Nikto targets web servers, and DirBuster targets HTTP directories, not MQTT brokers.

34
Multi-Selectmedium

A security auditor is performing a penetration test on an operational technology (OT) network utilizing Modbus/TCP. Which THREE of the following actions can an attacker typically perform if network segmentation and firewall rules are improperly configured? (Choose THREE)

Select 3 answers
A.Write to coils and holding registers to manipulate actuator states and setpoints
B.Send diagnostic or reset commands (e.g., Function Code 0x08) to cause controller reboots
C.Automatically decrypt Active Directory Kerberos ticket-granting tickets stored on the PLC
D.Read holding registers and input registers to harvest process variables and sensor data
E.Execute cross-site scripting (XSS) attacks against the PLC's internal browser rendering engine
AnswersA, B, D

Modbus write commands can be exploited to alter critical industrial control setpoints and override safety limits.

Why this answer

Modbus/TCP lacks built-in security, meaning any host with network access can read registers, write/alter register values, and send stop/start commands to PLCs.

35
MCQeasy

A security researcher is analyzing an embedded Linux firmware image for potential backdoors. The researcher wants to quickly scan the binary for compressed file systems, bootloader signatures, and kernel versions without extracting it. Which command-line tool is best suited for this initial identification task?

A.Wireshark
B.Binwalk
C.Metasploit Framework
D.Aircrack-ng
AnswerB

Binwalk analyzes binary images to identify embedded files, headers, file systems (like SquashFS, JFFS2), and compressed archives.

Why this answer

Binwalk is the industry-standard tool for searching binary images for embedded file systems and executable code signatures.

36
MCQeasy

During a wireless penetration test of an industrial plant, an auditor wants to discover all active Wi-Fi access points and associated IoT wireless clients operating in the 2.4 GHz band. Which wireless auditing tool should the auditor use to monitor and dump 802.11 management frames?

A.Hydra
B.Airodump-ng
C.Sqlmap
D.Nbtscan
AnswerB

Airodump-ng listens to raw 802.11 frames, displaying AP BSSIDs, channel numbers, encryption types, and connected client MAC addresses.

Why this answer

Airodump-ng is the premier tool included in the Aircrack-ng suite for capturing 802.11 wireless frames in monitor mode.

37
Multi-Selecthard

A penetration tester is evaluating a smart home hub communicating via Z-Wave protocol. Which TWO of the following characteristics or security mechanisms distinguish Z-Wave from standard Wi-Fi or Zigbee implementations? (Choose TWO)

Select 2 answers
A.Relying on standard IEEE 802.11 physical layer framing and MAC headers
B.Utilizing the Security 2 (S2) framework featuring Elliptic Curve Diffie-Hellman (ECDH) key exchange
C.Operating on sub-GHz radio frequencies (typically 868 MHz in Europe and 9084 MHz in the US)
D.Requiring all participating nodes to maintain an active BGP routing table with upstream Internet routers
E.Operating natively on the 5 GHz Wi-Fi frequency band with WPA3-Enterprise authentication
AnswersB, C

Modern Z-Wave implementations utilize S2 security, providing robust encryption and secure key agreement via ECDH.

Why this answer

Z-Wave operates on sub-GHz frequencies (avoiding 2.4 GHz congestion) and incorporates S2 (Security 2) framework using ECDH for secure key exchange.

38
MCQhard

A security researcher is performing dynamic analysis of an IoT firmware binary inside an emulated MIPS environment using QEMU-user mode. When executing the binary, the application crashes with a segmentation fault due to missing dynamic library dependencies in the emulated root directory. Which environment variable must be exported to instruct QEMU where to search for the target root filesystem's shared libraries?

A.QEMU_ROOTFS
B.LD_LIBRARY_PATH
C.QEMU_LD_PREFIX
D.PATH
AnswerC

Setting QEMU_LD_PREFIX points the QEMU user-mode emulator to the directory containing the rootfs libraries, resolving missing dependency errors.

Why this answer

When running binaries under QEMU user-mode emulation, the QEMU_LD_PREFIX environment variable specifies the path to the root directory containing the target architecture's libraries.

39
MCQmedium

During a hardware penetration test of an IoT device, the tester identifies a 4-pin header on the PCB. Using a multimeter, the tester measures ground on pin 1, 3.3V on pin 4, and observes fluctuating voltages on pins 2 and 3 during boot. What hardware interface do pins 2 and 3 most likely represent?

A.UART (Universal Asynchronous Receiver-Transmitter)
B.JTAG (Joint Test Action Group)
C.I2C (Inter-Integrated Circuit)
D.SPI (Serial Peripheral Interface)
AnswerA

UART interfaces commonly feature VCC, GND, TX, and RX pins, presenting active data signal fluctuations during device bootup.

Why this answer

UART (Universal Asynchronous Receiver-Transmitter) interfaces typically consist of 4 pins: VCC, GND, TX, and RX, where TX and RX show fluctuating voltage activity during transmission upon boot.

40
MCQmedium

A security analyst is performing a penetration test against a building automation system utilizing BACnet over IP. To discover BACnet devices on the local subnet without prior knowledge of their IP addresses, which specific network packet type and destination should the analyst send?

A.A UDP broadcast packet containing a BACnet Who-Is request sent to port 47808
B.An ICMP ping sweep to identify all live IP addresses on the local network segment
C.An SNMP GETBULK request using the default private community string
D.A TCP SYN scan directed at port 47808 across the entire subnet
AnswerA

BACnet devices respond to a Who-Is broadcast message sent to UDP port 47808 by returning an I-Am message containing their device instance and IP address.

Why this answer

BACnet/IP uses a global broadcast UDP packet sent to port 47808 (0xBAC0) with a Who-Is service request to discover devices. Unicast TCP requests require prior IP knowledge, ICMP echo requests only show active hosts not BACnet services, and SNMP queries require a known community string.

41
MCQhard

A penetration tester is assessing an industrial MQTT broker that requires client authentication but lacks Access Control Lists (ACLs). The tester successfully connects using valid credentials. Which attack technique can the tester leverage to perform denial-of-service against sensitive actuator topics?

A.Executing an MQTT-specific TCP SYN flood against port 1883
B.Subscribing to the '$SYS/#' system topic hierarchy using wildcard expansion
C.Sending a CONNECT packet with an invalid keep-alive timer value of zero
D.Publishing retained messages with empty payloads to critical command topics
AnswerD

Retained messages are stored by the broker. Sending an empty payload as a retained message to a critical topic forces subscribers to instantly receive a null/cleared state, disrupting operational control.

Why this answer

In MQTT, if ACLs are missing, any authenticated client can publish to any topic. A malicious publisher can flood or retain empty messages on critical command topics to cause a denial-of-service.

42
MCQmedium

A security consultant is performing a penetration test against a smart building HVAC system controlled by BACnet/IP. The consultant wants to discover BACnet devices and their supported object properties on the local subnet. Which utility or Python tool specifically designed for BACnet protocol assessment should the consultant use?

A.ettercap
B.bacpypes (using scripts like whois.py / iam.py)
C.sqlmap
D.msfvenom
AnswerB

bacpypes is an implementation of the BACnet protocol stack in Python, providing scripts to execute Who-Is broadcasts and discover devices.

Why this answer

The 'bacpypes' Python library and its associated command-line scripts are widely used by testers to interact with and enumerate BACnet devices.

43
MCQhard

A penetration tester is evaluating a Zigbee-based smart home lighting network. Using a Texas Instruments CC2531 USB dongle flashed with Sniffer firmware, the tester captures over-the-air packets. To decrypt the Zigbee application layer payload in Wireshark, what critical piece of cryptographic material must the tester input into Wireshark's Zigbee decryption settings?

A.The 128-bit Zigbee Network Key (NWK key)
B.The device's physical serial number printed on the casing
C.The manufacturer's IEEE 802.15.4 MAC address
D.The Wi-Fi WPA2 pre-shared key of the local router
AnswerA

Wireshark requires the 128-bit Network Key to decrypt standard Zigbee frames captured over the air.

Why this answer

Zigbee networks encrypt application data using a Network Key. To inspect encrypted application payloads in Wireshark, the Network Key must be provided in the Zigbee protocol preferences.

44
MCQhard

A security analyst is performing a security assessment on a Siemens S7-1200 PLC. Using Nmap, which NSE script should the analyst run to gather detailed device information, including rack, slot, and firmware version via the S7 communication protocol?

A.s7-info
B.modbus-discover
C.bacnet-info
D.enip-info
AnswerA

The 's7-info' NSE script connects to TCP port 102 and retrieves Siemens S7 controller identification details.

Why this answer

Nmap includes specific industrial control scripts in the 'scripts/' directory. The 's7-info' script specifically queries Siemens S7 devices to extract operational data.

45
MCQhard

An ethical hacker is performing a security review of a smart energy grid employing IEC 60870-5-104. The hacker wishes to inject a forged ASDU (Application Service Data Unit) command to open a circuit breaker. Using Python, which library can the hacker use to construct and transmit raw IEC 104 application layer frames over TCP?

A.BeautifulSoup
B.Pandas
C.Pygame
D.Scapy
AnswerD

Scapy provides packet crafting capabilities and supports industrial protocol layers for network injection and protocol testing.

Why this answer

Scapy is a powerful Python-based packet manipulation library that allows building custom packets for industrial protocols like Modbus, DNP3, and IEC 104.

46
MCQmedium

A penetration tester is analyzing the firmware of an IoT smart bulb extracted via a flash dump. Using Binwalk, the tester extracts the squashfs-root file system. Which command should the tester execute to search for hardcoded private RSA keys within the extracted directory?

A.strings -k squashfs-root/
B.grep -rn 'BEGIN RSA PRIVATE KEY' squashfs-root/
C.firmadyne -s squashfs-root/
D.binwalk -A squashfs-root/
AnswerB

Searching recursively for the standard PEM header 'BEGIN RSA PRIVATE KEY' inside the extracted file system effectively uncovers hardcoded private keys.

Why this answer

Binwalk is great for extraction, but searching the file system for specific file signatures like private keys is effectively done using grep with regular expressions or specialized tools like 'find' combined with cryptographic headers.

47
Multi-Selecthard

An engineering team is hardening an Operational Technology (OT) network segment that relies on legacy SCADA protocols lacking native encryption or authentication. Which THREE compensating controls should the penetration tester recommend to mitigate risks associated with these insecure protocols? (Choose THREE)

Select 3 answers
A.Disable all TCP and UDP ports on the SCADA network switches
B.Deploy industrial Intrusion Detection Systems (IDS) tuned for OT protocol anomalies
C.Deploy network segmentation adhering to the ISA/IEC 62443 zones and conduits model
D.Implement industrial firewalls capable of Deep Packet Inspection (DPI) for SCADA protocols
E.Install traditional endpoint antivirus software directly on the Programmable Logic Controllers (PLCs)
AnswersB, C, D

An OT-aware IDS can detect unauthorized write commands, firmware uploads, or abnormal register queries.

Why this answer

Legacy SCADA protocols like Modbus, DNP3, and S7comm lack native authentication and encryption. Compensating controls include deploying industrial firewalls (deep packet inspection), implementing network segmentation (air-gapping or zones/conduits per ISA/IEC 62443), and using industrial intrusion detection systems (IDS). Antivirus on PLCs is typically not feasible, and disabling all TCP ports is impossible since the protocols require them.

48
Multi-Selectmedium

A penetration tester is evaluating the security posture of an industrial SCADA network. Which THREE of the following operational technology (OT) vulnerabilities are most commonly found during network penetration tests of legacy control systems? (Choose THREE)

Select 3 answers
A.Lack of cryptographic authentication on control commands (allowing spoofing)
B.Strict implementation of mandatory end-to-end TLS 1.3 encryption on all internal PLC racks
C.Cleartext transmission of industrial control protocols (e.g., Modbus, Telnet)
D.Automatic hardware-level isolation preventing any lateral movement from the corporate IT network
E.Use of default or hardcoded service credentials on engineering workstations and PLCs
AnswersA, C, E

Many protocols like Modbus and DNP3 lack native message authentication, enabling attackers to inject arbitrary commands.

Why this answer

Legacy OT systems often lack encryption, authentication, and secure update mechanisms, exposing them to cleartext sniffing, command spoofing, and unauthenticated firmware updates.

49
MCQeasy

A tester is analyzing an IoT gateway that runs a web management interface. During discovery, the tester finds that the device exposes an unauthenticated API endpoint that accepts JSON input. Which command-line HTTP client should the tester use to send a custom POST request containing JSON data to test for command injection?

A.ping -c 4 -p '{"cmd":"id"}' 192.168.1.100
B.netstat -an | grep 80
C.traceroute -p 80 192.168.1.100
D.curl -X POST -H 'Content-Type: application/json' -d '{"cmd":"id"}' http://192.168.1.100/api
AnswerD

The curl command allows specifying the HTTP method (-X), headers (-H), and request body data (-d) to test API endpoints.

Why this answer

cURL is the standard command-line utility for transferring data with URLs, supporting custom HTTP methods, headers, and data payloads.

50
MCQeasy

During an assessment of an Operational Technology (OT) network, a tester discovers a Programmable Logic Controller (PLC) using the Modbus TCP protocol. The tester needs to query holding registers to understand the operational state of the industrial process. Which default TCP port should the tester target for Modbus communications?

A.Port 80
B.Port 502
C.Port 443
D.Port 1883
AnswerB

Port 502 is the official IANA assigned port for Modbus protocol communications.

Why this answer

Modbus TCP uses port 502 by default. Port 80 is HTTP, port 443 is HTTPS, and port 1883 is MQTT.

51
MCQhard

A penetration tester is analyzing an ARM-based IoT router firmware. The tester wants to statically analyze a compiled ELF binary named 'auth_service' to identify potential buffer overflows. Which open-source reverse engineering framework, developed by NSA, should the tester utilize to perform disassembly and decompilation of this binary?

A.Snort
B.Autopsy
C.Wireshark
D.Ghidra
AnswerD

Ghidra provides robust disassembly and decompiler support for embedded architectures like ARM, facilitating vulnerability identification.

Why this answer

Ghidra is an open-source reverse engineering suite developed by the NSA that supports multiple processor architectures, including ARM, MIPS, and PowerPC, making it ideal for IoT firmware analysis.

52
MCQeasy

An analyst is reviewing PCAP files captured from an ICS environment where Modbus/TCP traffic is flowing. The analyst notices cleartext commands being sent to alter coil values. Which tool can the analyst use to automatically extract Modbus registers and visualize the register state changes over time from the PCAP file?

A.John the Ripper
B.Wireshark
C.Hashcat
D.Dirb
AnswerB

Wireshark decodes Modbus/TCP packets natively, allowing the analyst to filter by 'modbus' and view function codes, reference numbers, and register values.

Why this answer

Wireshark includes built-in dissectors for Modbus/TCP and filters that allow inspecting every register read/write operation, making it the primary tool for packet-level ICS analysis.

53
MCQeasy

A tester is conducting a physical security and RF assessment against a wireless building automation system operating at 433 MHz. The tester wants to capture and replay the radio frequency signal emitted by a key fob to unlock a gate. Which hardware tool is specifically designed for software-defined radio (SDR) signal capture and analysis in this frequency range?

A.JTAGulator
B.Bus Pirate
C.Rubber Ducky
D.HackRF One / RTL-SDR
AnswerD

Software-defined radios like HackRF One and RTL-SDR tune into sub-GHz frequencies (such as 433 MHz) to capture, demodulate, and replay RF signals.

Why this answer

HackRF One, RTL-SDR, and similar software-defined radios are used for capturing RF signals. Specifically, devices like RTL-SDR or HackRF paired with GNU Radio or Universal Radio Hacker (URH) cover the 433 MHz band.

54
Multi-Selectmedium

When conducting a firmware security review of an embedded IoT device, a tester extracts the root filesystem and wants to identify potential memory corruption vulnerabilities introduced by compiler hardening settings. Which THREE security hardening flags or mechanisms should the tester verify are missing from the compiled binaries using tools like checksec? (Choose THREE)

Select 3 answers
A.Stack Canaries (Canary / GS)
B.Address Space Layout Randomization (ASLR)
C.Bandwidth Throttling
D.Read-Only Relocations (RELRO)
E.Non-Executable Bit (NX / DEP)
AnswersA, D, E

Stack canaries protect against stack-based buffer overflows by placing a sentinel value before the return address.

Why this answer

Checksec identifies binary protections such as RELRO, Stack Canaries, NX (No-Execute / DEP), and PIE (Position Independent Executable). ASLR is an OS-level feature, not a binary compilation flag. Therefore, Stack Canaries, NX, and RELRO are the correct binary compilation mitigations.

55
MCQmedium

A penetration tester is analyzing a proprietary IoT device protocol that operates over UDP. The tester has captured raw binary network traffic and wants to write a custom dissector script to parse the packet structure in Wireshark. What scripting language does Wireshark natively support for writing lightweight protocol dissectors?

A.Bash
B.PowerShell
C.Lua
D.Ruby
AnswerC

Wireshark has a built-in Lua interpreter that enables security analysts to quickly write custom protocol dissectors.

Why this answer

Wireshark supports Lua natively for writing post-dissection scripts, custom dissectors, and heuristic analyzers without needing to recompile the source code in C.

56
MCQhard

An attacker is performing a man-in-the-middle attack against an industrial control network utilizing the S7comm protocol between a Siemens S7-300 PLC and an engineering station. The attacker wants to inject malicious logic into the PLC memory. Which tool can be used to craft and send malicious S7comm packets to manipulate the PLC operating mode?

A.Snap7 library scripts
B.Aircrack-ng
C.Hydra
D.Wireshark
AnswerA

Snap7 provides a set of communication functions specifically designed to interface with Siemens S7 PLCs, allowing block reading, writing, and mode switching.

Why this answer

Snap7 is an open-source Siemens S7 communication library that allows developers and testers to interact with Siemens PLCs. Wireshark is passive, Metasploit has limited industrial modules, and Scapy can craft raw packets but Snap7 is the standard library for S7comm manipulation.

57
MCQhard

A pentester is performing a security review of a smart meter that utilizes an unencrypted CoAP (Constrained Application Protocol) service running over UDP. Using Python and Scapy, the tester crafts a packet to interact with the device. Which default UDP port should the tester target for standard unencrypted CoAP communications?

A.UDP 1900
B.UDP 5353
C.UDP 5060
D.UDP 5683
AnswerD

UDP port 5683 is the IANA-assigned default port for standard, unencrypted CoAP messaging.

Why this answer

CoAP is designed for resource-constrained internet devices and typically operates over UDP port 5683 for unencrypted traffic and port 5684 for secure DTLS traffic.

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