19 June, 2023

Finding Your Spidey Sense

Finding Your Spidey Sense

Welcome, fellow web-slingers of the digital realm! Like our friendly neighborhood superhero, Spider-Man, web application pentesters possess a unique "spidey sense" when uncovering vulnerabilities in web apps. But fear not! With some practice, you can develop a Spidey Sense of your own!  

A Web of Intrigue: Mapping the Attack Surface

As you begin your web app pentesting adventure, it's essential to understand the treacherous landscape you're about to explore. Dive into the realm of web technologies, frameworks, and coding languages.  This is why one of the initial steps is to map the attack surface the application exposes.  Let’s walk through some quick topics that I keep in mind as I work through an application test.

Unleashing Your Web-Slinging Skills

Imagine yourself as a web-slinging arachnid, gracefully mapping the intricate web of a web application's attack surface. Explore every nook and cranny, crawling through URL pathways like a curious spider hunting for bugs. Discover hidden or unlinked pages, mysterious directories, and intriguing URLs that may lead you to unexpected vulnerabilities. Did you come across something you need to become more familiar with? Google it! Embrace your curiosity because finding the unusual is where the fun begins in this tangled web!  

Unveiling the Secrets: robots.txt and the Elusive Site Map

Ah, robots.txt, the digital equivalent of a superhero's secret hideout. Sneak a peek into this enigmatic file and uncover its hidden treasures. More often than not, it will only relay basic or generic messages. However, if lucky, it may reveal directories and areas the application wants to keep hidden from prying eyes. Remember to check the application's sitemap.xml as well, a treasure map leading you to potential testing goldmines!

XSS: Exposing the Fun Side of Scripting Shenanigans

As you venture deeper, beware of the heartaches caused by Cross-Site Scripting (XSS). These vulnerabilities can allow villains to inject malicious scripts into innocent web pages. To uncover XSS vulnerabilities, keep your eyes peeled for those sneaky spots where user input is displayed without proper sanitization or encoding. These are prime targets where villains can inject their devious scripts.  But fear not, web-slingers! By identifying and exploiting these areas, you can demonstrate the potential risks and save the day!

Picture this: a comment section on a website where users can share their thoughts. If the application fails to sanitize and encode user-submitted comments, it's like leaving a window wide open for attackers to crawl in. They could inject a malicious script that runs whenever others view that page. The result? A gateway for unauthorized access, data theft, and chaos!

But how can you spot these hidden vulnerabilities and swing into action? Well, one trick is to try injecting common XSS payloads like <script>alert('Deadpool Was Here!')</script> into input fields. Watch closely how the application handles it. If the script executes or the payload is echoed back as is, you've hit the jackpot—an XSS vulnerability that needs immediate attention!

Remember, XSS vulnerabilities come in different flavors. There's the stored XSS, where injected scripts lurk in the server, waiting to strike multiple users. Then there's the reflected XSS, where scripts bounce right back to the user. Understanding these variations will make you a true web-slinging expert during your pentesting adventures.

Authentication, the Heroic Gateway

Authentication mechanisms are like the formidable gatekeepers of web apps. Test their strength, for within their defenses lie potential vulnerabilities. Does the application respond differently to password attempts for valid and invalid usernames? Then you have yourself a username enumeration flaw! Sometimes the login page doesn't give away too much information, but what about when you click "Forgot Password"? 

Beware the Curse of Insecure Direct Object References

As you navigate the web app's intricate maze, watch out for the curse of Insecure Direct Object References (IDOR). These loopholes grant unauthorized access to sensitive information or protected resources. Look for references to objects like user IDs, order numbers, or file names, and make sure proper authorization checks are in place. A true Spidey always respects access control!

The Quirky World of Error Messages

Ah, error messages, the unsung comedians of web apps. While their intentions may be noble, they often unintentionally spill the beans about the app's secrets. Keep an eye out for error messages that reveal sensitive information or divulge clues about the underlying technology. It's your job to ensure they keep their secrets hidden away!

Third-Party Sidekicks and Villainous Integrations

Third-party integrations can either be heroic sidekicks or mischievous villains. Examine their code and verify they're up to date and secure. Unpatched vulnerabilities in plugins or libraries can be a hacker's playground. Check to make sure those sidekicks are loyal and not villains in disguise!

With Great Power Comes Great Responsibility

These are just a few exciting things to look for during a web application pentest. With more practice, you can hone your skills until you're a master of identifying which threads to unravel. It's essential to maintain a curious mindset and explore various attack vectors to thoroughly assess the application's security posture.  If you want to see more of these types of things, check out our Slack workspace or sign up for our classes.  You can also jump into our advisory service if you want us to help you sling your webs. 

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