CEH Network and Web Application Attacks — 20 Questions

Question 1

During a penetration test, you notice that a web application accepts user input and displays it directly in the browser without sanitization. Which attack is most likely to succeed?

Accepted Answer

Cross-Site Scripting (XSS). Option C is correct because the scenario describes a classic reflected Cross-Site Scripting (XSS) vulnerability. The application accepts user input and displays it directly in the browser without sanitization, allowing an attacker to inject malicious JavaScript that executes in the victim's browser. This is the defining characteristic of XSS, not SQL injection or command injection, which target server-side interpreters.

Answer

SQL Injection

Answer

Cross-Site Request Forgery (CSRF)

Answer

Command Injection

Question 2

As a network defender, you notice an unusually high number of incomplete TCP three-way handshakes from a single external IP to multiple internal hosts. What is the most likely attack taking place?

Accepted Answer

SYN flood. A SYN flood attack exploits the TCP three-way handshake by sending a high volume of SYN packets to target hosts without completing the handshake (i.e., not sending the final ACK). This leaves the target with half-open connections, exhausting its connection table and denying service to legitimate traffic. The observation of incomplete handshakes from a single external IP to multiple internal hosts is a classic signature of a SYN flood.

Answer

UDP flood

Answer

ARP spoofing

Answer

ICMP flood

Question 3

A security analyst is configuring a web application firewall (WAF) to protect against SQL injection. Which HTTP parameter location should the analyst focus on to block malicious SQL queries?

Accepted Answer

Query string parameters. SQL injection attacks commonly target query string parameters because user input in URLs is often directly concatenated into SQL queries without proper sanitization. A WAF configured to inspect and filter query string parameters can block malicious SQL payloads before they reach the database server, as these parameters are the most frequent vector for such attacks.

Answer

Request body (POST data)

Answer

Cookie headers

Answer

User-Agent header

Question 4

You are performing a web application security assessment and discover that the application uses a hidden form field named 'price' to store the product price. The price is submitted with the form and used to process payments. Which attack would allow you to purchase an item for a lower price?

Accepted Answer

Parameter tampering. Parameter tampering is the correct answer because the 'price' field is stored in a hidden form field, which is client-side data that can be modified before submission. By intercepting the HTTP request (e.g., using a proxy like Burp Suite) and changing the 'price' value to a lower amount, the attacker can purchase the item at a reduced cost. This exploits the lack of server-side validation of the price parameter.

Answer

Directory traversal

Answer

Cross-Site Scripting (XSS)

Answer

Cross-Site Request Forgery (CSRF)

Question 5

A network administrator wants to prevent an attacker from using a network sniffer to capture traffic between a client and a web server. Which protocol should be enforced to encrypt all communication?

Accepted Answer

HTTPS. HTTPS (HTTP over TLS, RFC 2818) encrypts all communication between a client and a web server using TLS/SSL, preventing a network sniffer from capturing plaintext data such as cookies, URLs, or form submissions. This ensures confidentiality and integrity of the web traffic, directly countering passive eavesdropping attacks.

Answer

SNMP

Answer

FTP

Answer

HTTP

Question 6

Which TWO of the following are common web application vulnerabilities that allow an attacker to inject malicious code? (Select exactly 2)

Accepted Answer

Cross-Site Scripting (XSS). Cross-Site Scripting (XSS) is a common web application vulnerability that allows an attacker to inject malicious client-side scripts (typically JavaScript) into web pages viewed by other users. This occurs when an application includes untrusted data in a web page without proper validation or escaping, enabling the attacker to execute arbitrary code in the victim's browser within the context of the trusted site.

Answer

Brute Force

Answer

Path Traversal

Answer

Cross-Site Request Forgery (CSRF)

Question 7

Which THREE of the following are effective countermeasures against DNS poisoning attacks? (Select exactly 3)

Accepted Answer

Restrict recursive queries to trusted sources. Option B is correct because restricting recursive queries to trusted sources prevents attackers from using your DNS server as an open resolver to cache forged responses. By limiting recursion to authorized clients only, the server will not accept and cache DNS data from external, potentially malicious queries, which is a primary vector for DNS cache poisoning.

Answer

Use a single DNS server for all queries

Answer

Disable DNS caching

Question 8

Refer to the exhibit. A security analyst captured the HTTP request and response shown. What type of vulnerability is present?

Accepted Answer

Reflected Cross-Site Scripting (XSS). The HTTP response contains the search query parameter directly reflected in the HTML body without proper sanitization or encoding. Specifically, the request includes `?search=` and the response echoes this payload verbatim in the page content, allowing the browser to execute the injected JavaScript. This is the classic signature of a reflected cross-site scripting (XSS) vulnerability, where the malicious script is immediately reflected off the web server and executed in the user's browser.

Answer

Cross-Site Request Forgery (CSRF)

Answer

SQL Injection

Answer

Directory Traversal

Question 9

You are the lead security engineer for a financial technology company that hosts a critical web application on three load-balanced servers behind a reverse proxy. The application uses a REST API to process transactions. Recently, the company has experienced intermittent service outages during peak hours. Upon reviewing logs, you find that the reverse proxy is returning HTTP 503 errors for legitimate API requests, and the application servers show high CPU usage but normal memory. The network team reports no bandwidth issues. The application team claims no code changes were made. You suspect a specific type of attack is causing the outages. Which action should you take first to confirm the attack type?

Accepted Answer

Analyze the incoming request patterns in the reverse proxy logs to identify if there is a high volume of requests to a specific API endpoint.. Option B is correct because the symptoms—HTTP 503 errors, high CPU usage on application servers, normal memory, and no bandwidth issues—strongly suggest a Layer 7 DDoS attack, specifically an HTTP flood targeting a resource-intensive API endpoint. By analyzing reverse proxy logs for a high volume of requests to a specific endpoint, you can confirm the attack type (e.g., a slow loris or GET flood) before taking mitigation steps. This aligns with the CEH methodology of first identifying the attack vector through log analysis.

Answer

Configure the firewall to block all incoming traffic from the IPs that appear most frequently in logs.

Answer

Increase the number of application servers to handle the load.

Answer

Run a SQL injection scanner on the application.

Question 10

A penetration tester is analyzing a captured TCP session that includes a successful SQL injection attack. Which TWO of the following indicators would most likely confirm that the attack was successful?

Accepted Answer

The response contains database error messages or unexpected data. Option C is correct because a successful SQL injection often results in the database returning error messages or unexpected data directly in the HTTP response, confirming that the attacker's injected SQL statements were executed and returned results. This is a direct indicator of a successful attack, as the server processes the malicious input and includes database output in the response body.

Answer

The server redirects to a login page (302)

Answer

The server returns a 500 Internal Server Error

Answer

The client receives no response (timeout)

Question 11

Refer to the exhibit. A penetration tester executed the SQL injection payload and received the response shown. What is the most likely outcome of this attack?

Accepted Answer

The attacker extracted hashed passwords that can be cracked offline. The response shows a successful SQL injection that returned password hashes (likely from the `password` column) in the output. This indicates the attacker exploited a vulnerable parameter to extract hashed credentials from the database, which can then be cracked offline using tools like Hashcat or John the Ripper. The presence of hash strings in the response confirms data extraction, not modification or denial of service.

Answer

The attacker successfully performed a blind SQL injection to enumerate the database structure

Answer

The attacker caused a denial of service by sending an invalid query

Answer

The attacker modified the database records to update user passwords

Question 12

You are a security analyst for a medium-sized e-commerce company. The company hosts its web application on a single server running Apache on Ubuntu. Recently, the operations team noticed that the server's CPU usage spikes to 100% every few minutes, causing the website to become unresponsive. They have ruled out hardware issues. The web server logs show repeated requests to the same URL with varying parameters, such as /product?id=1, /product?id=2, etc., all originating from a single IP address. Each request returns a 200 OK response, but the server takes several seconds to generate the page. The application uses a relational database backend with an ORM. You suspect an attack is occurring. What is the most likely attack and the best immediate course of action?

Accepted Answer

Block the IP address of the attacker at the firewall. The attack is a resource exhaustion or application-layer DoS attack, where repeated requests to a database-backed endpoint (e.g., /product?id=1, /product?id=2) cause high CPU usage due to expensive ORM queries. The immediate best course is to block the single attacking IP at the firewall, as it stops the malicious traffic at the network perimeter with minimal overhead, preserving server resources for legitimate users.

Answer

Implement rate limiting on the /product endpoint

Answer

Install a web application firewall (WAF) to detect and block malicious requests

Answer

Apply input validation to ensure product IDs are positive integers

Question 13

Drag and drop the steps to recover a forgotten Windows administrator password using a bootable Linux USB into the correct order.

Question 14

Match each encryption algorithm to its type.

Question 15

Refer to the exhibit. A security analyst notices multiple ESTABLISHED connections on port 443 from different external IPs to the same process ID. What type of attack is most likely occurring?

Accepted Answer

Distributed denial-of-service (DDoS) attack

Answer

SSL/TLS renegotiation DoS

Answer

Slowloris attack

Answer

Man-in-the-middle attack

Question 16

Refer to the exhibit. A web server log shows requests from a single IP. Which vulnerability is being exploited?

Accepted Answer

Directory traversal

Answer

Cross-site scripting (XSS)

Answer

Remote file inclusion (RFI)

Answer

SQL injection

Question 17

Refer to the exhibit. A user visits a malicious site that returns this HTML. Which attack is being executed?

Accepted Answer

Cross-site request forgery (CSRF)

Answer

Cross-site scripting (XSS)

Answer

Session hijacking

Answer

Phishing attack

Question 18

Refer to the exhibit. An analyst runs an Nmap scan and finds these services. Which known vulnerability is most likely to be successfully exploited?

Accepted Answer

CVE-2021-41773 (Apache Path Traversal)

Answer

CVE-2017-5638 (Struts2 RCE)

Answer

CVE-2014-0160 (Heartbleed)

Answer

CVE-2020-1472 (Zerologon)

Question 19

Refer to the exhibit. A penetration tester sends a SOAP request and receives multiple user records. Which vulnerability is present?

Accepted Answer

SQL injection in SOAP service

Answer

XML External Entity (XXE) injection

Answer

Cross-site scripting (XSS)

Answer

Command injection