How to Hack a Server (Web)

By : Oliver Jones Oliver Jones
Hours Updated

⚡ Smart Summary

Web server hacking targets the software and misconfigurations behind websites that store valuable data such as passwords and credit card numbers. This page walks through how such attacks work and, more importantly, how to defend and harden a web server.

  • 🖥️ Target: Web servers hold credit card numbers, emails, and passwords, making them prime targets.
  • 🔎 Recon: Attackers profile a server through reverse-IP lookups and search-engine queries before probing.
  • 🐚 Web shells: An uploaded PHP shell gives an attacker file and database access.
  • 🧨 Attack types: Directory traversal, DoS, DNS hijacking, sniffing, phishing, pharming, and defacement.
  • 🛡️ Defense: Patch management, hardened configuration, firewalls, and vulnerability scanning cut risk.
  • 🤖 Modern edge: AI-driven WAFs flag web-shell uploads and anomalous requests in real time.
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How to Hack a Web Server

What is Web Server Hacking?

A web server is a computer program, or a computer, that runs the application. Its main function is accepting HTTP requests from clients and delivering web pages, then serving back HTTP responses. It could also be described as a virtual machine program. This type of delivery consists of HTML documents or additional content like style sheets and JavaScript.

Customers usually turn to the internet to get information and buy products and services. Towards that end, most organizations have websites. Most websites store valuable information such as credit card numbers, email addresses, and passwords, etc. This has made them targets for attackers. Defaced websites can also be used to communicate religious or political ideologies, etc.

In this tutorial, we will introduce you to web server hacking techniques and how you can protect servers from such attacks.

How to Hack a Web Server

In this practical scenario, we are going to look at the anatomy of a web server attack. We will assume we are targeting www.techpanda.org. We are not actually going to hack into it, as this is illegal. We will only use the domain for educational purposes.

Step 1) What we will need

Step 2) Information gathering

We will need to get the IP address of our target and find other websites that share the same IP address.

We will use an online tool to find the target’s IP address and other websites sharing the IP address.

YouGetSignal reverse IP domain check tool with the target domain entered

  • Click on the Check button
  • You will get the following results

Reverse IP lookup results listing domains sharing the target IP address

Based on the above results, the IP address of the target is 69.195.124.112.

We also found out that there are 403 domains on the same web server.

Our next step is to scan the other websites for SQL injection vulnerabilities. Note: if we can find an SQL-vulnerable page on the target, then we would directly exploit it without considering other websites.

  • Enter the URL www.bing.com into your web browser. This will only work with Bing, so do not use other search engines such as Google or Yahoo.
  • Enter the following search query
ip:69.195.124.112 .php?id=

HERE,

  • “ip:69.195.124.112” limits the search to all the websites hosted on the web server with IP address 69.195.124.112
  • “.php?id=” searches for URL GET variables used as parameters for SQL statements.

You will get the following results.

Bing search results listing pages that use GET parameters on the target IP

As you can see from the above results, all the websites using GET variables as parameters for SQL injection have been listed.

The next logical step would be to scan the listed websites for SQL Injection vulnerabilities. You can do this using manual SQL injection or use tools listed in this article on SQL Injection.

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Step 3) Uploading the PHP Shell

We will not scan any of the websites listed, as this is illegal. Let us assume that we have managed to log in to one of them. You will have to upload the PHP shell that you downloaded from http://sourceforge.net/projects/icfdkshell/

  • Open the URL where you uploaded the dk.php file.
  • You will get the following window.

Uploaded PHP shell interface showing access to files on the target server

  • Clicking the Symlink URL will give you access to the files in the target domain.

Once an attacker has access to the files, they can obtain login credentials to the database and carry out actions such as defacement or downloading data such as emails. This is exactly why the defensive measures later in this article matter.

Web Server Vulnerabilities

A web server is a program that stores files (usually web pages) and makes them accessible via the network or the internet. A web server requires both hardware and software. Attackers usually target the exploits in the software to gain unauthorized entry to the server. Let us look at some of the common vulnerabilities that attackers take advantage of.

  • Default settings – These settings, such as default user id and passwords, can be easily guessed by attackers. Default settings might also allow performing certain tasks, such as running commands on the server, which can be exploited.
  • Misconfiguration of operating systems and networks – certain configurations, such as allowing users to execute commands on the server, can be dangerous if the user does not have a good password.
  • Bugs in the operating system and web servers – discovered bugs in the operating system or web server software can also be exploited to gain unauthorized access to the system.

In addition to the above-mentioned web server vulnerabilities, the following can also lead to unauthorized access.

  • Lack of security policy and procedures – lack of a security policy and procedures, such as updating antivirus software and patching the operating system and web server software, can create security loopholes for attackers.

Types of Web Servers

The following is a list of the common web servers.

  • Apache – This is the commonly used web server on the internet. It is cross-platform but is usually installed on Linux. Most PHP websites are hosted on Apache servers.
  • Internet Information Services (IIS) – It is developed by Microsoft. It runs on Windows and is the second most used web server on the internet. Most asp and aspx websites are hosted on IIS servers.
  • Apache Tomcat – Most Java server pages (JSP) websites are hosted on this type of web server.
  • Other web servers – These include Novell’s Web Server and IBM’s Lotus Domino servers.

Types of Attacks against Web Servers

Attackers use several techniques against web servers, including the following:

  • Directory traversal attacks – This type of attack exploits bugs in the web server to gain unauthorized access to files and folders that are not in the public domain. Once the attacker has gained access, they can download sensitive information, execute commands on the server, or install malicious software.
  • Denial of Service Attacks – With this type of attack, the web server may crash or become unavailable to legitimate users.
  • Domain Name System Hijacking – With this type of attack, the DNS settings are changed to point to the attacker’s web server. All traffic that was supposed to be sent to the web server is redirected to the wrong one.
  • Sniffing – Unencrypted data sent over the network may be intercepted and used to gain unauthorized access to the web server.
  • Phishing – With this type of attack, the attacker impersonates a website and directs traffic to the fake website. Unsuspecting users may be tricked into submitting sensitive data such as login details, credit card numbers, etc.
  • Pharming – With this type of attack, the attacker compromises the Domain Name System (DNS) servers or the user’s computer so that traffic is directed to a malicious site.
  • Defacement – With this type of attack, the attacker replaces the organization’s website with a different page that contains the hacker’s name and images, and may include background music and messages.

Effects of Successful Attacks

  • An organization’s reputation can be ruined if the attacker edits the website content and includes malicious information or links to an inappropriate website.
  • The web server can be used to install malicious software on users who visit the compromised website. The malicious software downloaded onto the visitor’s computer can be a virus, Trojan, or botnet software, etc.
  • Compromised user data may be used for fraudulent activities, which may lead to business loss or lawsuits from the users who entrusted their details to the organization.

Best Web Server Attack Tools

Some of the common web server attack tools include the following:

  • Metasploit – this is an open source tool for developing, testing, and using exploit code. It can be used to discover vulnerabilities in web servers and write exploits that can be used to compromise the server.
  • MPack – this is a web exploitation tool. It was written in PHP and is backed by MySQL as the database engine. Once a web server has been compromised using MPack, all traffic to it is redirected to malicious download websites.
  • Zeus – this tool can be used to turn a compromised computer into a bot or zombie. A bot is a compromised computer that is used to perform internet-based attacks. A botnet is a collection of compromised computers. The botnet can then be used in a denial of service attack or for sending spam mails.
  • Neosplit – this tool can be used to install programs, delete programs, replicate them, etc.

Check this: 10 Best FREE DDoS Attack Tool Online

How to Avoid Attacks on Web Server

An organization can adopt the following policy to protect itself against web server attacks.

  • Patch management – this involves installing patches to help secure the server. A patch is an update that fixes a bug in the software. The patches can be applied to the operating system and the web server system.
  • Secure installation and configuration of the operating system.
  • Secure installation and configuration of the web server software.
  • Vulnerability scanning system – these include tools such as Snort, Nmap, and Scanner Access Now Easy (SANE).
  • Firewalls can be used to stop simple DoS attacks by blocking all traffic coming from the identified source IP addresses of the attacker.
  • Antivirus software can be used to remove malicious software on the server.
  • Disabling remote administration.
  • Removing default accounts and unused accounts from the system.
  • Default ports and settings (like FTP at port 21) should be changed to custom ports and settings (for example, an FTP port at 5069).

FAQs

Watch for unexpected new or modified files in web directories, unusual outbound connections from the server, spikes in resource use, unfamiliar admin accounts, and defaced pages. File integrity monitoring and log analysis surface most intrusions early.

A web shell is a malicious script, often PHP, that an attacker uploads to run commands through the browser. It grants remote control of the server — reading databases, editing files, and pivoting deeper — which is why blocking file uploads matters.

A WAF filters incoming HTTP traffic, blocking known attack patterns such as SQL injection, directory traversal, and web-shell uploads. It offers virtual patching against fresh vulnerabilities, but it is a filter, not a fix; you still apply the real software patch.

As soon as security patches are released. Attackers often weaponize a vulnerability within 24 hours of disclosure, so critical fixes cannot wait for a monthly cycle. Automate updates where possible and keep a tested rollback path.

Machine-learning models in modern WAFs learn normal request patterns, then flag anomalies such as web-shell uploads or unusual parameters in real time. They reduce false positives and can trigger blocking automatically, far faster than manual log review.

AI assistants like GitHub Copilot speed up writing input validation, parameterized queries, and configuration, but they also suggest insecure patterns. Treat output as a draft, run a security linter, and have a reviewer check it before deployment.

Only with written authorization from the system owner. Testing a server you do not own or lack permission to assess is a crime under laws such as the US Computer Fraud and Abuse Act. A bug-bounty scope defines exactly what is allowed.

Popular options include CEH, OSCP, and CompTIA Security+, with the CISSP covering security architecture broadly. They validate skills in vulnerability assessment, secure configuration, and defense that employers hiring for web security roles look for.

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