Pass the CertiProf Ethical Hacking Professional CEHPC Questions and answers with CertsForce

A "backdoor" is a method, often hidden or undocumented, of bypassing normal authentication or encryption in a computer system, cryptosystem, or algorithm. In the realm of managing information security threats, backdoors represent one of the most dangerous risks because they provide persistent, unauthorized access to a system without the knowledge of the administrators. Once a backdoor is established, the attacker can return to the system at any time, even if the original vulnerability they used to gain entry—such as a weak password or a software bug—has been patched.

Backdoors can be implemented in several ways. Some are "Software Backdoors," where a developer might intentionally (or accidentally) leave a hardcoded username and password in the code for debugging purposes. Others are "Malicious Backdoors" installed by a Trojan or a rootkit after a system has been compromised. For example, a hacker might install a "Reverse Shell" that periodically "calls home" to the attacker's server, asking for commands. This effectively creates a secret entrance that bypasses the firewall's inbound rules.

Managing this threat requires a multi-layered approach. "Integrity Monitoring" tools are essential; they alert administrators if system files or binaries are modified, which could indicate the presence of a backdoor. Additionally, "Egress Filtering" helps detect backdoors that attempt to communicate with an external Command and Control (C2) server. From an ethical hacking perspective, identifying backdoors is a key part of "Post-Exploitation." During a penetration test, the goal is not just to get in, but to show how an attacker could maintain their presence. By understanding that a backdoor is specifically designed to circumvent standard security checks, professionals can better implement "Zero Trust" architectures and regular auditing to ensure that the only way into a system is through the front door, with full authentication.

Cross-Site Scripting (XSS) is aweb application security vulnerabilitythat allows attackers to inject malicious client-side scripts into trusted web pages. This makes option A the correct answer. XSS occurs when applications fail to properly validate, sanitize, or encode user input before displaying it to other users.

When an XSS vulnerability is exploited, the injected script runs in the victim’s browser within the security context of the vulnerable website. This can lead to session hijacking, cookie theft, credential harvesting, keylogging, or redirection to malicious websites. XSS is commonly categorized intostored XSS, reflected XSS, and DOM-based XSS, all of which ethical hackers test during web application assessments.

Option B is incorrect because cloned websites are typically associated with phishing attacks, not XSS vulnerabilities. Option C is incorrect because XSS is primarily a web-based vulnerability, not a mobile-specific issue involving balance or contact theft.

From a defensive perspective, understanding XSS is critical for implementing secure coding practices such as input validation, output encoding, Content Security Policy (CSP), and proper use of modern frameworks. Ethical hackers test for XSS to help organizations prevent client-side attacks and protect user data.

A brute force attack is a trial-and-error method used to decode encrypted data such as passwords or Data Encryption Standard (DES) keys through exhaustive effort rather than intellectual strategies. The fundamental premise is that the attacker (or their software) attempts every possible combination of characters until the correct one is found. While it is technically "effective" in that it will eventually work given infinite time and resources, in practical application, it is often neither fast nor guaranteed to succeed.

The primary limitation of brute force attacks is time. As password complexity increases (the addition of uppercase letters, numbers, and special symbols), the number of possible combinations grows exponentially. For a high-entropy password, a standard brute force attack might take years or even centuries to complete, making it practically useless for an immediate breach. Furthermore, modern security systems implement "lockout" policies—such as freezing an account after three failed attempts—which effectively shuts down automated brute force attempts.

Ethical hackers distinguish between "pure" brute force and "dictionary attacks". A dictionary attack uses a pre-compiled list of common words and previously leaked passwords, which is significantly faster than trying every character combination but only works if the victim uses a common or weak password. To mitigate brute force risks, organizations use "salting" (adding random data to passwords before hashing) and multi-factor authentication (MFA). Therefore, while brute force remains a valid threat vector that must be tested, it is generally considered a "last resort" for an attacker due to its high time cost and high probability of detection or failure.

Google Dorks, also known as Google hacking, areadvanced search queriesthat use specific operators to locate publicly accessible information indexed by search engines. Therefore, option A is the correct answer.

Google Dorks donot hack systems, compromise computers, or act as backdoors. Instead, they reveal information that is already publicly available but may be unintentionally exposed due to poor configuration. Examples include exposed login pages, backup files, configuration files, error messages, or sensitive documents that should not be indexed.

Option B is incorrect because Google Dorks do not provide unauthorized access to web pages. Option C is also incorrect because Google Dorks do not exploit vulnerabilities or bypass authentication mechanisms.

From an ethical hacking perspective, Google Dorks are commonly used during thepassive reconnaissance phaseto identify information leakage without directly interacting with the target system. This makes them low-impact but highly effective for discovering misconfigurations.

Understanding Google Dorks is important for managing information exposure risks. Ethical hackers use them to demonstrate how attackers can gather intelligence without triggering security alerts. Defenders can mitigate these risks by properly configuring robots.txt files, access controls, and removing sensitive content from public indexing.

SQL Injection (SQLi) is a critical web security vulnerability that allows an attacker to interfere with the queries that an application makes to its database. It occurs when an application fails to properly sanitize or validate user input before including it in a Structured Query Language (SQL) command. By injecting malicious SQL code into an input field—such as a login form or a search bar—an attacker can trick the database into executing unintended commands.

The impact of a successful SQL injection attack can be devastating:

Data Theft: Attackers can bypass authentication to view sensitive information they are not authorized to see, such as user passwords, personal data, or credit card details.

Data Manipulation: An attacker can modify or delete data within the database, potentially leading to permanent data loss or the corruption of business records.

Identity Theft: By gaining access to user tables, attackers can take over administrative accounts.

Full System Compromise: In some configurations, SQLi can be used to gain access to the underlying server's operating system.

Ethical hackers test for SQLi by entering special characters (like ' or --) into input fields to see if the application returns a database error. Mitigation involves usingPrepared Statements(parameterized queries), which treat user input as data rather than executable code, and implementing strict input validation. Despite being one of the oldest web vulnerabilities, SQLi remains a top threat on the OWASP Top 10 list due to the prevalence of legacy code and poor coding practices.

Social engineering is an attack technique thatmanipulates human behaviorto gain unauthorized access to systems or information, making option A the correct answer. Asking users to disclose their passwords over the phone is a classic example of social engineering, often referred to as vishing (voice phishing).

Unlike technical attacks that exploit software vulnerabilities, social engineering targets human trust, fear, urgency, or lack of awareness. Attackers may impersonate IT staff, managers, or trusted vendors to convince victims to reveal credentials or perform harmful actions.

Option B is incorrect because antivirus software is a defensive security control, not an attack method. Option C is incorrect because updating the operating system is a security best practice that helps mitigate vulnerabilities.

From an ethical hacking standpoint, testing for social engineering vulnerabilities helps organizations understand their exposure tohuman-based attack vectors, which are among the most effective and commonly used by attackers. Ethical hackers may conduct controlled phishing simulations to assess employee awareness and response.

Mitigating social engineering attacks requires user training, security awareness programs, strong authentication methods, and clear verification procedures. Understanding social engineering is critical for building comprehensive defense strategies.

Netcat, often referred to as the“Swiss Army knife of networking,”is a versatile, open-source tool used for reading from and writing to network connections using TCP or UDP. This makes option B the correct answer. Netcat is widely used in ethical hacking, penetration testing, and system administration due to its flexibility and simplicity.

Netcat can perform a wide range of networking tasks, includingport scanning, banner grabbing, file transfers, reverse shells, bind shells, and debugging network services. It is commonly used during thereconnaissance, exploitation, and post-exploitation phasesof ethical hacking. Because of its ability to create raw network connections, it can simulate both client and server behavior.

Option A and option C are incorrect because Netcat iscross-platformand works on Linux, Windows, macOS, and other Unix-like systems. It is not limited to a single operating system, nor is it exclusively a hacking tool; it is also used legitimately by network administrators for troubleshooting and testing.

From a defensive security perspective, understanding Netcat is important because attackers frequently abuse it to establish unauthorized communication channels or backdoors. Ethical hackers use Netcat responsibly to demonstrate how weak configurations or exposed services can be exploited.

By identifying improper Netcat usage during assessments, organizations can improve monitoring, restrict unnecessary outbound connections, and strengthen endpoint security controls.

In computer security, a backdoor refers to ahidden method of accessing a system that bypasses normal authentication and security mechanisms, making option A the correct answer. Backdoors can be intentionally created by developers for maintenance purposes or maliciously installed by attackers after compromising a system.

From an ethical hacking perspective, backdoors are commonly discovered duringpost-exploitation activities. Attackers use them to maintain persistent access, even if passwords are changed or vulnerabilities are patched. Backdoors may take the form of hidden user accounts, modified services, malicious scripts, or hardcoded credentials.

Option B is incorrect because malware that spreads through instant messaging is typically classified as a worm or trojan, not specifically a backdoor. Option C is incorrect because a backdoor is not a legitimate or documented access point.

Understanding backdoors is essential for managing information security threats. Ethical hackers identify backdoors to demonstrate long-term risks and highlight weaknesses in system monitoring and access controls. Defenders can mitigate backdoor threats by implementing integrity monitoring, endpoint detection and response (EDR), regular audits, and strict access management.

Backdoors pose significant risks because they undermine trust in system security. Identifying and removing them is critical for restoring system integrity and preventing repeated compromise.

Persistent Cross-Site Scripting (XSS), also known as Stored XSS, is one of the most dangerous forms of web application vulnerabilities. It occurs when a web application receives data from a user and stores it permanently in its backend database or filesystem without proper sanitization or encoding. Common vectors for persistent XSS include comment sections, user profiles, message boards, and "Contact Us" forms. Unlike Reflected XSS, where the payload is included in a specific URL and only affects the user who clicks that link, a persistent XSS payload is served automatically to every user who visits the affected page.

When an attacker successfully injects a malicious script (typically JavaScript), the server "remembers" this script. Every time a legitimate user requests the page where the data is displayed, the server includes the malicious code in the HTML response. The user’s browser, trusting the source, executes the script. This can lead to devastating consequences, such as session hijacking through the theft of session cookies, account takeover, or the redirection of users to malicious websites. From an ethical hacking perspective, identifying persistent XSS involves testing all input fields that result in data being displayed later. Mitigation strategies focus on the principle of "filter input, escape output." Input should be validated against a strict whitelist of allowed characters, and any data rendered in the browser must be context-aware encoded (e.g., converting < to <) to prevent the browser from interpreting the data as executable code. Because the payload is stored on the server, this vulnerability represents a significant risk to the entire user base of an organization, making it a high-priority finding in any security assessment.

Shodan is aspecialized search engine designed to discover and index internet-connected devices, making option C the correct answer. Unlike traditional search engines that index websites, Shodan scans IP addresses to identify exposed services, open ports, device banners, and system metadata.

Shodan is widely used by ethical hackers, security researchers, and defenders to identify misconfigured or exposed systems such as webcams, routers, servers, industrial control systems, and IoT devices. It provides insight into how devices are exposed to the public internet.

Option A is incorrect because Shodan is not an application for food services. Option B is incorrect because Shodan does not function as a web browser or general-purpose search engine.

From an ethical hacking perspective, Shodan is often used duringpassive reconnaissanceto assess external attack surfaces without directly interacting with target systems. This helps organizations identify exposure risks before attackers exploit them.

Understanding Shodan reinforces the importance of proper configuration, firewall rules, and access control. Ethical hackers use Shodan responsibly to demonstrate how easily misconfigured devices can be discovered and targeted, encouraging stronger perimeter security and monitoring practices.