CPENT Iot And OT Exploitation — 30 Questions

Question 1

An IoT security analyst is performing a firmware security review of an embedded Linux router. Which TWO of the following static analysis techniques or tools should the analyst employ to identify hardcoded secrets and vulnerable binaries within the extracted root file system? (Choose TWO)

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Using 'grep' or 'strings' combined with regular expressions to search for API keys, passwords, and private certificates. Static analysis of firmware involves searching for hardcoded keys using pattern matching tools like 'grep' or 'Strings' and checking binary hardening properties using tools like 'checksec'.

Answer

Flashing a modified bootloader directly onto the physical SPI flash chip using a desoldered programmer

Answer

Capturing over-the-air 802.11 management frames using Wireshark

Question 2

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?

Accepted Answer

setenv bootargs ${bootargs} init=/bin/sh. 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.

Answer

tftp 0x80000000 kernel.bin

Answer

printenv mtdparts

Answer

run flash_os_image

Question 3

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?

Accepted Answer

Publishing retained messages with empty payloads to critical command topics. 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.

Answer

Executing an MQTT-specific TCP SYN flood against port 1883

Answer

Subscribing to the '$SYS/#' system topic hierarchy using wildcard expansion

Answer

Sending a CONNECT packet with an invalid keep-alive timer value of zero

Question 4

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?

Accepted Answer

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

Answer

modbus-discover

Answer

bacnet-info

Answer

enip-info

Question 5

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?

Accepted Answer

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

Answer

TCP 102

Answer

TCP 20000

Answer

UDP 44818

Question 6

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?

Accepted Answer

nRF Connect for Mobile. 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.

Answer

Hydra

Answer

Sqlmap

Answer

Aircrack-ng

Question 7

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?

Accepted Answer

UART (Universal Asynchronous Receiver-Transmitter). 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.

Answer

JTAG (Joint Test Action Group)

Answer

I2C (Inter-Integrated Circuit)

Answer

SPI (Serial Peripheral Interface)

Question 8

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?

Accepted Answer

The 128-bit Zigbee Network Key (NWK key). 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.

Answer

The device's physical serial number printed on the casing

Answer

The manufacturer's IEEE 802.15.4 MAC address

Answer

The Wi-Fi WPA2 pre-shared key of the local router

Question 9

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?

Accepted Answer

grep -rn 'BEGIN RSA PRIVATE KEY' squashfs-root/. 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.

Answer

strings -k squashfs-root/

Answer

firmadyne -s squashfs-root/

Answer

binwalk -A squashfs-root/

Question 10

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?

Accepted Answer

bacpypes (using scripts like whois.py / iam.py). The 'bacpypes' Python library and its associated command-line scripts are widely used by testers to interact with and enumerate BACnet devices.

Answer

ettercap

Answer

sqlmap

Answer

msfvenom

Question 11

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?

Accepted Answer

UDP 5683. 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.

Answer

UDP 1900

Answer

UDP 5353

Answer

UDP 5060

Question 12

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?

Accepted Answer

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

Answer

TCP 443

Answer

TCP 2404

Answer

TCP 44818

Question 13

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?

Accepted Answer

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

Answer

Wireshark

Answer

Metasploit Framework

Answer

Aircrack-ng

Question 14

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?

Accepted Answer

curl -X POST -H 'Content-Type: application/json' -d '{"cmd":"id"}' http://192.168.1.100/api. cURL is the standard command-line utility for transferring data with URLs, supporting custom HTTP methods, headers, and data payloads.

Answer

ping -c 4 -p '{"cmd":"id"}' 192.168.1.100

Answer

netstat -an | grep 80

Answer

traceroute -p 80 192.168.1.100

Question 15

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?

Accepted Answer

Ghidra. 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.

Answer

Snort

Answer

Autopsy

Answer

Wireshark

Question 16

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?

Accepted Answer

Function Code 16 (0x10) - Write Multiple Registers. 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.

Answer

Function Code 01 (0x01) - Read Coils

Answer

Function Code 04 (0x04) - Read Input Registers

Answer

Function Code 02 (0x02) - Read Discrete Inputs

Question 17

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?

Accepted Answer

Wireshark. 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.

Answer

John the Ripper

Answer

Hashcat

Answer

Dirb

Question 18

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?

Accepted Answer

mitmproxy. 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.

Answer

Airodump-ng

Answer

Ncat

Answer

Hping3

Question 19

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?

Accepted Answer

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

Answer

Bash

Answer

PowerShell

Answer

Ruby

Question 20

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?

Accepted Answer

HackRF One / RTL-SDR. 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.

Answer

JTAGulator

Answer

Bus Pirate

Answer

Rubber Ducky