Web App Penetration Testing Interview Questions

• It allows being proactive in the real-world approach of evaluating IT infrastructure security.  

• It allows staying on top of your security and can help prevent financial loss. 

• It helps to detect multiple attacks and respond accordingly on time. 

• Judge how successfully network defenses perform when encountering an attack.

• It will give an independent view of the effectiveness of existing security processes.

Symmetric encryption uses one private key for both encryption and decryption, while asymmetric encryption uses a public key for encryption and a private key for decryption. It is more secure than the symmetric key encryption technique but is much slower.

Vulnerability Testing is also known as Vulnerability Assessment which is a process that detects and classifies security loopholes in the infrastructure. Mobile Application VAPT helps uncover such vulnerabilities and ensures that it is secure enough to use in your organization.

Before carrying out a penetration test, all the data associated with the software is carefully backed up because the test might affect the data to prove the software's vulnerability. Protecting the data is a priority before, during, and even after pentesting. Cloud storage, external secure hard drives, etc. are some good options to back up the copies of data. 

The whole point is to have a backup for your data in case of any damage.

An Intrusion Detection System (IDS) is a device or software application that monitors network traffic for malicious activity or policy violations. Any malicious activity or violation is reported or collected centrally using a security information and event management system.

Root causes of the security vulnerability are:

• Complexity: Security vulnerabilities rise proportionally with complexity. Complex information, software, hardware, businesses, and processes can all introduce security vulnerabilities.

• Open connections: Each open connection is vulnerable to exploitation. 

• Poor Password Protection: Passwords are meant to secure virtually everything from mobile devices to websites, software, company VPNs, and enterprise software. Despite knowing about the dangers, people still write, share or give passwords out to websites. 

• Poor Management: Security is a management problem. Hence organizations need to manage things while keeping security in mind— built into training, processes, and IT. 

• User Input: Accepting user input by phone or internet can introduce security vulnerabilities. Firstly the data can be fraudulent or incorrect. Secondly, electronically received data can be designed to attack the receiving system.

Secure Sockets Layer (SSL) is the standard technology for keeping an internet connection secure, whether it be client to client, server to server, or client to server. 

This prevents hackers from reading and modifying any information transferred, including potential personal details.  

TLS (Transport Layer Security), is essentially SSL, but more secure and updated. It provides privacy, authentication, and data integrity over computer networks and is used in instant messaging, web browsing, email, and more. 

TLS is more reliable because it was designed to address known SSL vulnerabilities and support stronger, more secure algorithms.

Some of the tools used for penetration testing are:

• Netsparker

• Hackerone

• Wireshark

• Burp Suite 

• Nessus

• Metasploit

The time taken to perform a pentest depends on multiple parameters like the nature, size, and security level of the software. It also depends on the type of testing, the type and number of systems, and any engagement constraints. Typical engagements have an average testing time of 1 to 3 weeks.

Yes. Penetration testing can cause damage to the networks and systems. It is because the real exploits and attacks are carried out to test the systems for security. Hence, it is suggested to back up all sorts of data before going for penetration testing.

• It monitors the work of firewalls, routers, key servers, and files. It uses its extensive attack signature database to raise the alarm and send notifications in case of a breach.

• By using the signature database, IDS ensures quick detection of known anomalies with a low risk of false alarms. 

• It analyzes different types of attacks, identifies malicious content, and helps the administrators organize and implement effective controls.

• It helps the organization maintain regulatory compliance and meet security regulations because it provides greater visibility across the entire network.

• Information Gathering: The first step in penetration testing is information gathering. The organization being tested needs to provide information about in-scope targets to the penetration tester. 

• Reconnaissance: In this step, penetration testers identify additional information that may have been overlooked, unknown, or not provided. 

• Discovery and Scanning: This process involves using tools to analyze the target systems. Pentesters commonly perform static or dynamic analysis, checking the system's code for bugs or security gaps.

• Gaining Access: This stage uses web app attacks to uncover a target's vulnerabilities. Testers then try and exploit these vulnerabilities by stealing data or intercepting traffic to understand the damage they can cause.

• Maintaining access: The goal is to see if the vulnerability can be used to achieve a persistent presence in the exploited system - long enough for a bad actor to gain in-depth access. 

Analysis: The results of the penetration test are compiled into a report detailing what vulnerabilities they discovered in their test, sensitive data that was accessed, the amount of time the pen tester was able to remain in the system undetected.

Threat modeling is a practice for identifying potential threats to an organization's network security. It can be argued that threat modeling can be the most effective way of managing and improving your cyber security posture.

Yes, penetration testing should be performed on a regular basis to ensure more consistent IT and network security management by revealing how newly discovered threats or emerging vulnerabilities might be exploited by malicious hackers. Penetration testing should be conducted any time if any of the following issues arise:

• When a new infrastructure or web application is installed on the network

• When any business physically moves or adds another site to their network

• When security patches are applied

• When IT Governance requires it.

STRIDE is an acronym used to identify a thread modeling technique. 

S - Spoofing

T - Tampering

R - Repudiation

I - Information disclosure

D - Denial of Service (DoS)

E - Elevation of privilege

In order to identify, analyze, and correct the threats to a system, a company must adopt this threat modeling technique.

2FA: Two Factor Authentication

• 2S2D: Double-Sided Double-Density

• 2VPCP: Two-Version Priority Ceiling Protocol

• 3DES: Triple Data Encryption Standard

• 3DESE: Triple Data Encryption Standard Encryption

• 3DESEP: Triple Data Encryption Standard Encryption Protocol

Discovery & Pre-engagement Tasks: This is the first phase of penetration testing, where the reconnaissance activities are performed on the target system. 

Here, the aim is to find and collect as much information as possible about the target. This information can be the IP address, user names, email addresses, job titles, and more.

Attempt to Penetration: After collecting the information, the pentesters can start finding and testing the loopholes. The aim of this phase is to identify the entry points and attempt to penetrate the system and gain access. Once they compromise the target system, the next step is to find access to other environments in an attempt to reach the admin privileges. 

Analyze and Create a Report: While attempting the penetration, the pen testers should keep track of every point. It helps them to create the report of their analysis with all the details. They can highlight the entry points, vulnerabilities, as well as other weak points inside the system.

In the report, the pen testers also include the next possible steps that can be taken, priorities to be set, and the methods to remediate the loopholes.

Remediation: Using the report created in the previous phase, organizations can get information about the weaknesses in their systems. The next step is to evaluate the right ways to remediate the vulnerabilities in order to prevent the attacks.

Retesting: After doing the remediation, it is time to retest the entire environment again. The pentesting needs to be done frequently for the new apps, infrastructure, and networks. Sometimes, new vulnerabilities may also arise because of outdated tools or systems. So, pentesting remains an ongoing process.

A penetration test is also known as a pen test, is a simulated cyberattack against your computer system to check for exploitable vulnerabilities. The main objective of pentesting is to identify exploitable issues so that effective security controls can be implemented.

The primary goals of pentesting are to:

• Secure confidential data

• Detect loopholes in the system

• Find vulnerabilities in apps

• Assess the impact of cyberattacks on business

• Meet the regulatory security compliances

• Apply strong security strategy

The primary purpose of pentesting is to perceive the business through the eyes of an attacker and proactively thwart their attacks. It measures the feasibility of systems or end-user compromise and evaluates any related consequences such incidents may have on the involved resources or operations.

Vulnerability testing is the process of assessing or reviewing the vulnerabilities or security weaknesses in a system. Vulnerability assessment helps in finding whether the system is prone to cyber-attacks so that the vulnerabilities discovered can be removed.

Vulnerability assessment can assist in preventing several types of threats like SQL injection, XSS, insecure settings in software or apps, privileges because of faulty mechanisms, etc. 

In contrast to vulnerability assessment, penetration testing involves identifying vulnerabilities in a particular network or infrastructure. These vulnerabilities can be there in the system because of misconfigurations, poor architecture, insecure programming, etc.

Pentesting will provide an actionable report about vulnerabilities so that pentesters or security analysts can fix them and implement further best practices. The vulnerabilities discovered during pentesting are assigned a severity score or risk rating to prioritize their remediation.

The three types of penetration testing are:

• Black-Box Testing

• White-Box Testing

• Gray-Box Testing

Black Box Penetration Testing

The pentesters have no information regarding the IT infrastructure in a black box test. The hackers will have to find their own way into the system and plan how to orchestrate a breach.

White Box Penetration Testing

The pentesters team has information about the target system before starting to work. The goal of a white-box penetration test is to conduct an in-depth security audit of a business's systems. 

Gray Box Penetration Testing

In the grey box penetration test, the pentesters have partial knowledge about or access to an internal network. A grey box pen test allows the team to focus on the targets with the greatest risk and value from the start.

There are usually three types of teams used:

• The red team

• The blue team

• The purple team

The Red Team: The Red Team is independent of the company and hired to covertly test its defenses. The team often consists of independent ethical hackers who evaluate system security in an objective manner. Their objective is to identify and safely exploit vulnerabilities in the target's cybersecurity or physical perimeters.   

The Blue Team: The Blue Team consists of security professionals who monitor all alerts, anomalies, and any other form of suspicious behavior within the IT infrastructure. 

The Purple Team: It exists to ensure and maximize the effectiveness of the Red and Blue teams. They combine the Blue Team's defence and detection capabilities with the threats and vulnerabilities found by the Red Team.

For a penetration tester to become recognized in this field, the below certifications are a must:

• The Certified Ethical Hacker (CEH – this is administered by the EC Council)

• The Offensive Security Certified Professional (OSCP – this is administered by Offensive Security)

Cross-site Scripting is a kind of injection where hackers write and execute malicious scripts into websites. This can be done through browsers. The injections become successful when the vulnerabilities in the website or web app take the input without any validation and show the output. 

Using XSS attacks, the hackers can send the malicious code to other end users of the source and gain access to cookies, session tokens, as well as other confidential details in the browser.

The five types of penetration testing techniques are:

• Network Service Penetration Testing

• Web Application Penetration Testing

• Wireless Penetration Testing

• Social Engineering Penetration Testing

• Physical Penetration Testing

Some of the common pentesting tools are:

• HTTPS (Port #443)

• NTP (Port #123)

• FTP (Port #’s 20 & 21)

• SSH (Port #22)

• Telnet (Port #23)

• HTTP (Port #80)

• SMTP (Port #25)

In such instances, "Nmap" is the most commonly used tool.

SQL injection or SQLi is a prevalent attack vector where the malicious SQL code is executed to tamper or compromise the backend database. SQL injections make the confidential information and data accessible, which was not supposed to be displayed. 

The data exposed through SQLi can be the sensitive information of an organization, users, customer data, etc.

These attacks can hamper the credibility of a business, as well as cause the deletion of important data. Sometimes, the attackers can also find admin access to the database, which can cause big losses.

Symmetric key cryptography relies on a shared key between two parties, while Asymmetric key uses both a private and public key, where one key is used to encrypt and the other one to decrypt.

Symmetric cryptography is more efficient and is more suitable for encrypting and decrypting large volumes of data. In contrast, Asymmetric cryptography is not much efficient and is therefore used only for exchanging a shared key after the symmetric key is used.

Some of the following characteristics are:

• A peer certificate

• The session identifier

• An established compression method

• Any associated cipher specs

Three different types of cross-site scripting attacks are there:

• Stored XSS: Also called Persistent or Type I attack, the Stored XSS is caused when the inputs by the users are stored on the server. 

• Reflected XSS: Reflected XSS, also known as Non-persistent or Type II, is caused when the web app or website shows the errors to user input instantly. 

• DOM-Based XSS: DOM-based XSS or Type 0 injections occur when the source of data, sink, as well as the data flow, all take place in the DOM.

CSRF stands for cross-site request forgery. It is a type of attack that makes authenticated users enter requests against the web app with which they have the authentication. This makes the web app lose the trust of the authenticated user. 

In case the web app can't identify the difference between the requests by the specific users, the hackers can exploit the vulnerability. The hackers then force the authenticated users to enter malicious requests, which can result in the submission of transactions, buying products, modifying passwords, deleting records, etc. 

This scenario can be avoided in two ways:

• Double-check the specific CSRF token used

• Confirm that the specific requests are coming from within the same origin

Omniquad BorderSecure is a service that performs network-based audits or even automated pentesting of an entire network infrastructure. It can give pentesters detailed information and data as to how the cyber-attacker can gain access to your network-based digital assets. It can be used to help mitigate any form of threat that a malicious third party launches.