Web server penetration testing is an assessment that uses ethical hacking to uncover vulnerabilities in an organisation’s web servers and applications.
Ethical hackers typically use manual and automated methods to simulate a genuine attack on a system. Because this way, they can find hidden security issues and insecure development practices that may cause a serious breach later. With the average cost of a data breach rising to $4.35 million in 2023, most organisations are taking every step to prevent their sensitive information from being exploited.
But if you're thinking of diving into the ethical hacking business, you might wonder which web server penetration testing best practices you should follow. After all, there are several approaches you could take as a red teamer!
In this go-to guide, we'll cover the best practices for web server penetration that will set every hack up for success. From setting clear objectives to writing a stellar report, these tactics will give you all the confidence you need to attack your next pentest.
Web server penetration testing best practices
Set clear objectives with the client
Web server penetration testing best practices actually start before a red teamer is officially engaged in an active hack.
Before you start hacking a system, you’ll need to speak with the client and have them outline the intended scope of the pentest. Then, you'll want to ensure the client tells you what type of penetration test they’re looking for.
So, check whether they want:
· A blind, black-box test with absolutely no information about the company’s systems
· White-box testing that gives you credentials, server information, and network maps to make access easier
· A grey-box test that mixes both approaches and usually offers the pentester login credentials but little else to start with
Once you’ve established the type of penetration test you’ll carry out, it’s time to define the scope. Do they want you to identify critical assets with a narrow approach? Would they prefer that you apply broad testing covering as many assets as possible?
You’ll also establish an expected testing time frame during this period, as the depth of testing depends entirely on budget and available resources.
If you’re in any doubt, you’ll be in a good position if you can do the following during the scoping stage:
1. Align your test with the organisation’s objectives
2. Ensure a comprehensive coverage of assets
3. Create a manageable testing environment that’ll help you optimise your exploiting efforts
Define your testing methodologies and choose a standard approach
Most of the time, you’ll follow a specific pattern when carrying out a penetration test. This will include scoping, reconnaissance, scanning, exploitation and attack, reporting, and mitigation suggestions for the client.
However, this isn’t always the path that you'll follow, as white-box testing often skips the reconnaissance phase. However, it's a good rule of thumb if you're looking for web server penetration testing best practices, as it's virtually foolproof.
After you've figured out the client's intended approach, you should map out a plan of attack. This will often include scanning for open ports, targeting employees with phishing emails, and checking for vulnerabilities using scanning tools.
Carry out subdomain enumeration and authentication bypass
Before heavily exploiting a system, you'll want to make your attack surface as wide as possible. After all, that's precisely what a malicious hacker would do! So, along with uncovering hidden or private content across a web server, you should also use subdomain enumeration and authentication bypass mechanisms.
These will allow you to access unpermitted areas of an organisation's web applications. And by discovering countless subdomains, you can even encourage users to click through to insecure HTTP pages. This process is critical to the reconnaissance phase, which grey and black-box hackers must carry out.
Although this list isn’t exhaustive, you’ll likely use the following techniques and tools during this phase (but feel free to get creative!):
· Cache poisoning
· Brute forcing for passwords and login credentials
· Session hijacking (usually using Burp Suite and Firesheep)
· Man in the Middle (MITM) attacks to get hold of sensitive information and intercept communications between end users and web servers
As you delve deeper and hit the exploitation phase, things get much more interesting as hackers have partial or full access to a company’s online web system.
Find and exploit common vulnerabilities in web servers
It's a great idea to tackle the top web application vulnerabilities during your initial scans. Not only will this reveal where an organisation is falling short with its cyber security, but it'll also help them patch issues that modern hackers are currently targeting.
From unsecured administrative access and privilege issues to SQL injection attacks, denial of service, and cryptographic failures, red teamers can test many things.
Web server penetration testing best practices involve digging as deep as possible. While you'll be on a set timescale for your hack, you'll want to look at the following exploitations, as they'll show you a great deal about an organisation's vulnerabilities.
· Authentication bypass issues
Use the right tools
Following web server penetration testing best practices means having the top tools to hand. Realistically, a great hacker is only so powerful without the right weapons in their arsenal!
If your client asks you to target specific applications during your test, you'll want to use the most relevant tools. However, you'll probably play around with the following tools during your penetration test (and a few others!).
· Burp Suite: To intercept and modify web traffic, help with brute-forcing, and carry out fuzzing attacks.
· OWASP ZAP: To detect vulnerabilities like SQL injection and XSS while offering scanning capabilities.
· SQLMAP: An automatic SQL injection tool that identifies vulnerabilities and allows data dumping and unauthorised access.
· Vega: An open-source web application vulnerability scanner that seriously speeds up your process with automated scanning (that’s incredibly user-friendly).
· Wireshark: Wireshark is a network packet analyser that can intercept and log packets flowing across a network.
Pay careful attention to your reporting
Although the bulk of your work will take place during the scanning and exploitation phase of a pentest, reporting well is crucial if you’re following web server penetration testing best practices.
Every single penetration report should cover the following things:
· A summary of what happened during the hack (this should include an executive summary written in non-technical language that C-suite members can understand!).
· Details of the vulnerabilities you uncovered and how you exploited them. For this stage of the report, use technical language that security professionals and DevOps teams will understand.
· This section provides an overview of the potential impact on the business if this hack were carried out in real terms. The Common Vulnerability Scoring System (CVSS) can be used to show how business-critical these vulnerabilities could be if exploited.
· Strategic recommendations to patch the vulnerabilities. This can include everything from better privilege access management to more effectively managing subdomains to reduce risk.
Ready to put these penetration testing best practices to the test?
TryHackMe’s innovative training modules allow you to tackle penetration testing techniques in a hands-on, accessible, and gamified way. Whether you’re interested in walking through file inclusion or want to understand how to find and exploit IDOR vulnerabilities in a live lab setting, we’ve got you covered.
Ben Spring