Speaker 1: What if you could get paid to break things, I
Speaker 1: mean legally and ethically find hidden weaknesses in the digital
Speaker 1: armor of some really big tech companies.
Speaker 2: Yeah, it sounds a bit counterintuitive, doesn't it. Yeah, but
Speaker 2: it's a real thing.
Speaker 1: We're diving into, well, a pretty fascinating field today where
Speaker 1: curiosity meets critical thinking and you know, the payout can
Speaker 1: actually be quite impressive.
Speaker 2: It's true. We're talking about the world of web security
Speaker 2: and bug bounty hunting. It's a really crucial front line
Speaker 2: in protecting well, pretty much everything we do online now.
Speaker 1: Absolutely, so today we're doing a deep dive into bug
Speaker 1: bounty hunting for web security. Our mission really is to
Speaker 1: cut through the jargon, understand the core ideas, the clever
Speaker 1: techniques and the essential tools that let security pros find
Speaker 1: these vulnerabilities in web apps, right.
Speaker 2: And how they help prevent malicious attacks and yeah, sometimes
Speaker 2: even or in a nice bounty for doing it.
Speaker 1: And this deep dive it pulls insights from a pretty
Speaker 1: comprehensive guide, right, an experts view on the let's say,
Speaker 1: offensive side of bug hunting exactly.
Speaker 2: We're going to unpack how ethical hackers think, what specific
Speaker 2: weaknesses they target, and the frankly powerful tools they use
Speaker 2: in this constant sort of digital chess match.
Speaker 1: Okay, let's get into it then. So the big question first,
Speaker 1: why why would someone actually dedicate their time to hunting
Speaker 1: for bugs? What's the real pull?
Speaker 2: Well, there are a few pretty strong motivations actually. First,
Speaker 2: it just makes you a better security professional, plain and simple.
Speaker 2: If you understand how attackers operate, you get way better
Speaker 2: at defending.
Speaker 1: That makes sense, know your enemy kind.
Speaker 2: Of thing precisely. Second, there's well a huge element of recognition,
Speaker 2: you know, respect within the cybersecurity community. Finding a critical
Speaker 2: bug in a major platform that really builds your credibility fast.
Speaker 1: And the money you mentioned bounties.
Speaker 2: Oh yeah, and of course the financial side can be significant.
Speaker 2: It's definitely not uncommon for top hunters to earn substantial
Speaker 2: sums for finding really high impact vulnerabilities.
Speaker 1: That's a key point. It's not some niche hobby anymore.
Speaker 1: Big names like Google, Facebook, Twitter, they aren't just putting
Speaker 1: up with this, They're actively encouraging it with their own
Speaker 1: bug bounty programs.
Speaker 2: Right, It's become a standard practice. It's a win win really.
Speaker 2: They get their security strengthened and skilled people get rewarded
Speaker 2: for finding the flaws.
Speaker 1: What's really interesting, though, is the ethical angle. The guide
Speaker 1: is clear on this, isn't it?
Speaker 2: Oh, absolutely crystal clear. You're learning these attacking techniques quote
Speaker 2: unquote specifically for defense. You're essentially becoming a white hat
Speaker 2: hacker or maybe a penetration tester to find those flaws
Speaker 2: before the h the actual bad guys do.
Speaker 1: So the knowledge is like a shield, not a weapon,
Speaker 1: for causing trouble.
Speaker 2: Exactly, never from malpractice.
Speaker 1: Which naturally brings up the legal side. There's a very
Speaker 1: bright line here. You just cannot cross.
Speaker 2: Cannot stress this enough. You must never ever attack systems
Speaker 2: without the owner's explicit permission. Seriously, this is an.
Speaker 1: Optional and the consequence if you do they can be severe.
Speaker 2: It's against the law in many places, and it could
Speaker 2: easily end a potential career before he even gets off the ground.
Speaker 2: Just don't do it.
Speaker 1: Okay. So for someone starting out thinking this sounds interesting,
Speaker 1: how do they get that permission? How do they stay legal?
Speaker 2: The advice is pretty straightforward. Register with established bug bounty platforms,
Speaker 2: you know places like bug crowd Hacker, one, Cobalt, there's
Speaker 2: even the Japan bug bounty program Anti hack.
Speaker 1: These platforms provide the framework.
Speaker 2: Yeah, they act as the intermediary, They provide the legal sandbox.
Speaker 2: The rules of engagement are clear, so you know you're
Speaker 2: operating within legitimate boundaries.
Speaker 1: Got it. But finding these exploits, it's not like just
Speaker 1: running a quick scan is it sounds like it takes
Speaker 1: some serious effort.
Speaker 2: Oh. Absolutely, there's a steep learning curve involved, no doubt.
Speaker 2: You need a pretty deep understanding of how web applications
Speaker 2: are built, the HGTP protocol itself, different encoding schemes, all
Speaker 2: the different types of attacks out there.
Speaker 1: So it's less about just knowing the it's much.
Speaker 2: More about understanding the underlying logic. You know how the
Speaker 2: web actually works and where those fundamental building blocks can
Speaker 2: be well twisted or subverted.
Speaker 1: Okay, so if you had to boil it down, what
Speaker 1: is a bug bounty hunter? A simple definition?
Speaker 2: Sure, At its core, a bug bounty hunter is an
Speaker 2: ethical hacker who gets paid to find vulnerabilities in software
Speaker 2: and websites. Simple as that, really, but pretty powerful.
Speaker 1: That's a great summary. Now, Okay, someone's intrigued, they're thinking
Speaker 1: about trying this, But you can't just start poking around
Speaker 1: on say Google's live servers. Right, you need a safe space.
Speaker 1: Why is setting up a virtual lab so vital for beginners?
Speaker 2: It's absolutely crucial paramount even because it lets you practice
Speaker 2: using all these hacking tools legally and more importantly, safely
Speaker 2: on your own system.
Speaker 1: Like a digital sandbox exactly like that.
Speaker 2: Think of it as a controlled test chamber. If some
Speaker 2: malicious code gets loose, or maybe a tool doesn't behave
Speaker 2: as expected, it's all contained with in that simulated environment.
Speaker 2: It won't trash your main computer.
Speaker 1: Ah okay, so it protects your actual machine.
Speaker 2: Right, it's your personal risk free playground. You can just experiment,
Speaker 2: try everything that comes into your head without worrying about
Speaker 2: breaking anything important or accidentally attacking someone else.
Speaker 1: Makes perfect sense, like a crash test dummy for your
Speaker 1: digital experiments. So what tools and setups do you recommend
Speaker 1: for building this virtual lab?
Speaker 2: For beginners? Virtual Box is usually the top recommendation. It's
Speaker 2: super versatile because it runs on pretty much any operating
Speaker 2: system Windows, Linux, Mac OS, so.
Speaker 1: It works wherever you are.
Speaker 2: Yeah, it's compatibility and relative ease of use make it
Speaker 2: a really good starting point for setting up a security lab.
Speaker 1: And once you have virtual Box running, what os should
Speaker 1: you install inside it for this kind of work.
Speaker 2: Colie Linux is definitely the go to choice for most
Speaker 2: people starting in ethical hacking.
Speaker 1: Why Collie specifically because.
Speaker 2: It comes preloaded with just a massive suite of essential
Speaker 2: security tools, hundreds of them. It just streamlines the setup
Speaker 2: process incredibly. You basically get a hacker's toolkit ready to
Speaker 2: go right out of the virtual box.
Speaker 1: Okay, that's convenient. So we've got Collie running inside virtual box.
Speaker 1: What are the first few core tools someone would likely
Speaker 1: start using to actually hunt for vulnerabilities.
Speaker 2: Well, you'll quickly become familiar with tools like burp suite
Speaker 2: and wasp bz ABP. These are what we call interception proxies.
Speaker 1: Interception proxies. How do they work?
Speaker 2: Imagine like a control tower for your web traffic. Every
Speaker 2: single piece of information your browser sends to a website
Speaker 2: or receives back passes through this tool.
Speaker 1: First, so you can see everything exactly.
Speaker 2: They capture all the traffic from the web application you're targeting,
Speaker 2: just less you inspect it, analyze it, even modify requests
Speaker 2: before they hit the server or responses before they reach
Speaker 2: your browser.
Speaker 1: Like being a man in the middle, but for ethical reasons.
Speaker 2: Precisely give you incredible control and visibility. But it's also
Speaker 2: really important to remember relying on just one tool that's
Speaker 2: usually a bad idea in this field. Why is that
Speaker 2: because no single tool catches everything. Different tools have different strengths,
Speaker 2: different ways of looking at things, So having a diverse
Speaker 2: toolkit is always always better for doing comprehensive testing. You'll
Speaker 2: miss things otherwise, right.
Speaker 1: So it's not about one magic bullet tool, but building
Speaker 1: an arsenal. And where do you practice with these tools
Speaker 1: if you can't just point them at live websites?
Speaker 2: Ah, that's where applications like webgoat come in. It's deliberately
Speaker 2: designed to be insecure, built to be broken pretty much.
Speaker 2: It's made by OAS, the Open Web Application Security Project,
Speaker 2: specifically for learning and testing common web app vulnerabilities. You
Speaker 2: run it locally, usually on your own machine, at an
Speaker 2: address like http dot localhost dot a zero a zero web.
Speaker 1: Gooat, and because it's local and designed for testing, you.
Speaker 2: Can experiment as much as you want, try all sorts
Speaker 2: of attacks without any legal risk whatsoever. It's the perfect
Speaker 2: training ground.
Speaker 1: Are there other Linux distributions besides Collie that ethical hackers
Speaker 1: sometimes use? Maybe for more specialized.
Speaker 2: Oh sure, Kalli is the most popular, but there are others.
Speaker 2: Black Arts, linuxes well a behemoth. It boasts something like
Speaker 2: over nineteen hundred tools pre installed.
Speaker 1: Wow.
Speaker 2: Yeah. Then for users who want extreme security through isolation,
Speaker 2: there's quebsos. It compartmentalizes everything into separate, isolated virtual machines. Interesting,
Speaker 2: and you also have things like in pre doos which
Speaker 2: uses the anonymous IP network and hunix, which leverages the
Speaker 2: tour network for you know, enhance privacy and anonymity. Each
Speaker 2: has its niche.
Speaker 1: Okay, so we've covered the why and the how to
Speaker 1: set up our ethical hacking playground. Now for the really
Speaker 1: juicy stuff, let's dive into some specific web vulnerabilities. Often
Speaker 1: ethical hackers start by looking for subtle tricks, right like
Speaker 1: cross site requests forgery or CSRF.
Speaker 2: What exactly is that CSRF? Yeah, often pronounced sea surf.
Speaker 2: It's an attack where a malicious request gets sent from
Speaker 2: a user's browser without them even knowing it or intending it.
Speaker 1: How does that work? How can my browser send something
Speaker 1: I didn't ask it to?
Speaker 2: Think of it like this? Your already logged into your bank,
Speaker 2: right your browser has a valid session cookie. The attacker
Speaker 2: tricks your browser into submitting another request to your bank,
Speaker 2: say to transfer money, leveraging that existing logged in session.
Speaker 2: Your browser just does what it's told, thinking the request
Speaker 2: is legitimate because.
Speaker 1: While you're logged in, so the users logged in, everything
Speaker 1: seems normal. How does the attacker actually trigger that unwanted request?
Speaker 2: They can create a seemingly harmless web page, maybe with
Speaker 2: just an image or a link on it. Hidden on
Speaker 2: that page is an HTML form. When your browser lows
Speaker 2: that page, maybe even just the hidden image pixel, some
Speaker 2: JavaScript in the background like document dot form zero dot submit,
Speaker 2: automatically submits that hit en form.
Speaker 1: And because my browser is already logged into the vulnerable.
Speaker 2: Site exactly, that malicious request often just sails right through
Speaker 2: the defenses because it includes your valid session cookies, the
Speaker 2: server thinks you sent it.
Speaker 1: Wow, So it's less about injecting bad code and more
Speaker 1: about tricking the browser into being an unwitting accomplice.
Speaker 2: That's a great way to put it. Bloids the trust
Speaker 2: between a user's browser and the site they're logged into.
Speaker 1: So how do developers stop this? What's the key defense
Speaker 1: against CSRF?
Speaker 2: The core defense is using CSRF tokens for every action
Speaker 2: the user takes that changes something like changing a password
Speaker 2: or sending money, the server should require a secret, unique,
Speaker 2: unpredictable token to be submitted along with the request, and
Speaker 2: this token proves it proves that the request really originated
Speaker 2: from the legitimate user interface on the site itself and
Speaker 2: not from some malicious third party page. Yeah, credit for
Speaker 2: is a request. If the token is missing or invalid,
Speaker 2: the server just rejects the action.
Speaker 1: Fascinating. Okay, Next up, cross site scripting XSS. This one
Speaker 1: feels like it's been around forever, but it's still a
Speaker 1: huge problem, right.
Speaker 2: Oh, absolutely, EXSS is still incredibly common. It involves injecting
Speaker 2: malicious browser site scripts, usually it's JavaScript, into a web application.
Speaker 1: How does that injection happen?
Speaker 2: Typically it's because user input fields aren't properly sanitized or validated.
Speaker 2: Think about a comment section on a blog or a
Speaker 2: search bar. If I can type something like scriptrol create
Speaker 2: been hacked script into that field and.
Speaker 1: The website just displays it as raw HTML.
Speaker 2: Exactly, then every single user who views that page or
Speaker 2: maybe sees that search result will have my malicious script
Speaker 2: run in their browser within the context of the trusted website.
Speaker 1: So attackers are basically probing every place a user can
Speaker 1: type something in looking for a spot where raw HTML
Speaker 1: or jobscript might slip through.
Speaker 2: The cracks precisely. And the reason it's so hard to
Speaker 2: prevent entirely, especially on huge complex applications like say Google
Speaker 2: or Facebook, is just the sheer scale. You have thousands
Speaker 2: of developers, millions of lines of code ensuring every single
Speaker 2: input fuel everywhere perfectly strips out every potentially harmful tag
Speaker 2: or script. It's a monumental challenge.
Speaker 1: Just one little oversight can open a huge door.
Speaker 2: A massive door. That's why EXSS remains one of the
Speaker 2: most prevalent vulnerabilities found by bug hunters.
Speaker 1: So the core insight here isn't just about the script itself,
Speaker 1: is it. It's about how absolutely critical every single point
Speaker 1: of user input becomes. A tiny mistake can compromise potentially
Speaker 1: everyone using the site.
Speaker 2: That's exactly it. The impact can be widespread.
Speaker 1: How would a hacker approach finding EXSS in a safe
Speaker 1: test environment like one of those deliberately vulnerable.
Speaker 2: Apps, Well, using something like o WASP, Broken Web Application
Speaker 2: or BWPP. You'd start by systematically trying to inject simple
Speaker 2: jobscript snippets into various input fields. You know, like that
Speaker 2: basic alert Hello, this is reflected XSS.
Speaker 1: Payload, just to see if anything executes.
Speaker 2: Yeah, just to see if you get that pop up box.
Speaker 2: And tools like burp suite and o wasp ZAPPI are
Speaker 2: indispensable here. Zapip, for instance, is really helpful because it
Speaker 2: doesn't just flag potential vulnerabilities with those colored alerts red
Speaker 2: for high risk, orange for medium, yellow for low.
Speaker 1: It tells you how to fix it.
Speaker 2: Too often, yes, it'll suggest concrete solutions, like maybe adding
Speaker 2: the x frame options ny header to prevent certain types
Speaker 2: of attacks like clickjacking, which is related.
Speaker 1: So z adp gives you a bit of a roadmap
Speaker 1: for both finding and fixing the issue.
Speaker 2: It definitely can and for more systematic testing, maybe trying
Speaker 2: lots of different EXSS variations. Burp Suite's intruder tool is
Speaker 2: incredibly powerful. You can feed it a whole list of
Speaker 2: known EXSS payloads and just automate the process of sending
Speaker 2: them to various input fields looking for responses that indicate
Speaker 2: your script actually executed successfully.
Speaker 1: Okay, let's switch gears to header injection and URL redirection.
Speaker 1: What's the basic weakness here what allows this kind of attack?
Speaker 2: This vulnerability pops up when an application takes user input,
Speaker 2: maybe from a URL parameter, and uses it directly to
Speaker 2: decide where to redirect the user's browser without properly checking
Speaker 2: or validating that input first.
Speaker 1: So instead of sending you to a safe fixed.
Speaker 2: Location right, instead of having SAFECode like header location dot https,
Speaker 2: do wwwang dot site hard coded, the vulnerable code might
Speaker 2: look more like response dot send, redirect, request dot get parameter,
Speaker 2: or just blindly trust whatever URL the user or attacker
Speaker 2: provides in that parameter, and.
Speaker 1: That opens the door to what's the main risk for
Speaker 1: the user.
Speaker 2: The biggest risk is usually very convincing phishing attacks. An
Speaker 2: attacker can craft a special URL that looks like it
Speaker 2: belongs to the legitimate website, but when you click it,
Speaker 2: that vulnerable redirect parameter sends your browser seamlessly to a
Speaker 2: malicious site designed to steal your credentials or drop malware.
Speaker 1: Because it came from the trusted site initially, the user
Speaker 1: might not notice the switch exactly.
Speaker 2: It makes the fish much harder to spot. It really
Speaker 2: exploits that user trust in the original domain.
Speaker 1: So how do ethical hackers track down these hidden potentially
Speaker 1: malicious redirects.
Speaker 2: Again, Bripsweet's proxy and spider tools are key. As you
Speaker 2: browse the target application, you're keeping an eye out for
Speaker 2: any HTTP responses that come back with a three xx
Speaker 2: status code that three to one means a redirect is happening.
Speaker 1: And once you spot a three xx redirect, then you.
Speaker 2: Take that request over to Burp's repeater tool. There you
Speaker 2: can manually tamper with the parameter that seems to be
Speaker 2: controlling the redirect destination. If you can change it to
Speaker 2: point to an external site you control, and the browser
Speaker 2: successfully redirects there, you've confirmed the vulnerability, and.
Speaker 1: If you find one, what's the fix you'd recommend?
Speaker 2: Well, the best fix is usually to just avoid using
Speaker 2: user controlled data in redirection logical together if possible. If
Speaker 2: a redirect is necessary based on input, then use direct
Speaker 2: hard coded links mapped to save values, or maintain a
Speaker 2: very strict server side whitelist of allowed destination ur else.
Speaker 1: Whitelisting sounds safer.
Speaker 2: Definitely and absolutely crucial. Any user input that might influence
Speaker 2: a redirect destination must be strongly validated. Check that it
Speaker 2: starts with an expected trusted prefix like http dot your
Speaker 2: site dot com and doesn't contain characters that could trick
Speaker 2: the browser.
Speaker 1: Okay, next up a real classic malicious file uploads. What's
Speaker 1: the immediate danger if an attacker can successfully upload a
Speaker 1: bad file?
Speaker 2: Oh, the danger is huge. If an attacker can upload
Speaker 2: a malicious file, especially something like a PHP script or
Speaker 2: another executable file type, and then get the server to
Speaker 2: run it, that can give them a significant foothold on
Speaker 2: the system, leading to what It could lead to them
Speaker 2: completely owning the system, as they say, getting full control,
Speaker 2: or at the very least, maybe defacing the website changing
Speaker 2: its content. It's basically a form of remote code execution.
Speaker 2: You're potentially letting the attacker run their own programs directly
Speaker 2: on your server.
Speaker 1: Yikes. How does a poorly secured file upload form look
Speaker 1: compared to a safe one?
Speaker 2: An insecure one might be just a basic HTML form
Speaker 2: form action upload, PHP method, posting type, multipart from data,
Speaker 2: maybe with little or no checking happening on the server side.
Speaker 2: It just sort of trusts whatever file the user sends.
Speaker 1: It as a secure one.
Speaker 2: A secure site implements robust validation on the server after
Speaker 2: the file arrives. It would check the file extension sure,
Speaker 2: But more importantly, it would check the actual file type
Speaker 2: based on its content, not just the name. Maybe scan
Speaker 2: it from malware and sure it matches an allowed list
Speaker 2: of types like only accepting JPEGs or PDFs, and reject
Speaker 2: anything suspicious, especially executable scripts like PHP.
Speaker 1: So how would an attacker try to bypass these checks?
Speaker 1: In a test lab like DVWA.
Speaker 2: They often rely on tricks and misconfigurations. For example, you
Speaker 2: might try uploading a malicious PHP file containing commands like
Speaker 2: slixick elsli to list files or mk to hacker to
Speaker 2: create a directory.
Speaker 1: But the server might block dot php files.
Speaker 2: Right, so if the server only checks the last part
Speaker 2: of the file name, you might try naming your file
Speaker 2: something like shell dot php dot jpg. You hope the
Speaker 2: server sees dot jpg and allows it, but maybe later
Speaker 2: another part of the system interprets it as dot php
Speaker 2: and executes it clever.
Speaker 1: What else?
Speaker 2: You'd also use burp Suite's repeater tool to modify the
Speaker 2: request on the fly. You can change the content type
Speaker 2: heater that the browser sends, maybe setting it to image jpg.
Speaker 2: Even though you're uploading PHP code. You're trying to fool
Speaker 2: the server side validation logic and if it works. If
Speaker 2: it works, you might send see visible changes like website defacement,
Speaker 2: or maybe you can navigate to a new directory like
Speaker 2: hacker that your malicious script created that confirms your code executed.
Speaker 2: It's definitely a game of cat mouse with the servers
Speaker 2: validation rules.
Speaker 1: Okay, let's shift slightly towards email security poisoning Sender Policy
Speaker 1: Framework or SBF. Most of us just send and receive
Speaker 1: emails without thinking much about this. What does SBF actually do?
Speaker 2: SBF is a technical standard for email authentication. Its main
Speaker 2: job is to help protect both email senders and recipients
Speaker 2: from spam, from email spoofing where someone pretends to be
Speaker 2: someone else, and from phishing attacks.
Speaker 1: How does it do that?
Speaker 2: It works by allowing a domain owner, like say, your company,
Speaker 2: to publish a list of mail servers that are authorized
Speaker 2: to send email on behalf of that domain. When an
Speaker 2: email arrives, the receiving server checks the sender's IP address
Speaker 2: against this published SBF record for the domain.
Speaker 1: Sort of like a bouncer checking an ID against a
Speaker 1: guest list.
Speaker 2: That's a great analogy. Yeah, if the sending server isn't
Speaker 2: all list, the receiving server can be suspicious and might
Speaker 2: mark the email as spam or even rejected outright.
Speaker 1: Why do we need this extra layer? Doesn't basic email
Speaker 1: handle authentication?
Speaker 2: That's good question. The fundamental email protocol SMTP is actually
Speaker 2: quite old and well surprisingly trusting. It doesn't have strong
Speaker 2: authentication built in. It's relatively easy for someone to forge
Speaker 2: the from address on an email.
Speaker 1: So SPF plugs that gap exactly.
Speaker 2: It adds a much needed layer of verification on top
Speaker 2: of the basic SMTP process.
Speaker 1: Okay, so it's important, but does it have limitations? And
Speaker 1: I hear about DMRC too, what's that about.
Speaker 2: Yes, SPF definitely has limitations. Yeah. One major one is
Speaker 2: that it doesn't actually validate the frumheader the address the
Speaker 2: recipient ces and their email client. It checks the envelope from,
Speaker 2: which is used more for routing behind the scenes.
Speaker 1: Ah, so it might not stop spoofing of the visible
Speaker 1: address correct.
Speaker 2: Also, SPF can sometimes break when emails are legitimately forwarded
Speaker 2: because the forwarding server might not be listed in the
Speaker 2: original domains sp F record. That's where DMRC comes in.
Speaker 1: What is dmrcad.
Speaker 2: DMR, which stands for Domain based Message Authentication Reporting and Conformance,
Speaker 2: builds upon both SPF and another standard called DKIM. It
Speaker 2: provides much stronger protection against spoofing and fizzing. Crucially, DMR
Speaker 2: allows domain owners to tell receiving servers exactly what to
Speaker 2: do with emails that fail SPF or DKEM checks, like
Speaker 2: quarantine them or reject them. And it provides really valuable
Speaker 2: reports back to the domain owner about who is sending
Speaker 2: email using their domain, helping them spot fraudulent activity.
Speaker 1: So better protection and visibility. How would someone check if
Speaker 1: their domain's SPF record is set up correctly?
Speaker 2: They're easy to use online tools for that. Good examples
Speaker 2: are Kidderman dot com, SPF validate dot html, or the
Speaker 2: tools on mxtoolbox dot com. You just put in your
Speaker 2: domain name say Sunjipsynha, dot fund, and these tools will
Speaker 2: fetch and analyze its published SPF record. They'll show you
Speaker 2: what it is like VSPF one plus A plus MX
Speaker 2: plus IP four point nine, four point one three zero
Speaker 2: point one nine, put one two four all and tell
Speaker 2: you it looks correctly formated, helping you spot in years useful.
Speaker 1: Okay, Next on our list, XML External Entity injection or XX.
Speaker 1: Now many people know XML is a way to structure data,
Speaker 1: right How does that lead to an attack?
Speaker 2: Right? First, quick recap. XML is a markup language, software
Speaker 2: and hardware independent used for storing and transporting data. It's
Speaker 2: self descriptive, kind of like a structured text file, maybe
Speaker 2: similar in concept to a database table in some ways.
Speaker 1: Is it still used much? I hear more about JSON now.
Speaker 2: Jason has definitely become more popular for webapis, but XML
Speaker 2: is still very widely used, especially in enterprise systems, configuration files,
Speaker 2: industry specific standards things like SOPU web services. It's definitely
Speaker 2: not gone away.
Speaker 1: And what's a DTD? You mentioned that in the context
Speaker 1: of XML.
Speaker 2: A DTD or document type definition basically defines the rules
Speaker 2: for an XML document. It specifies what elements and attributes
Speaker 2: are allowed, their structure, ensuring the XML is valid according
Speaker 2: to a specific format.
Speaker 1: Okay, so XML is just structured data. DTD defines the structure.
Speaker 1: Where does the injection part and the danger come from?
Speaker 2: The danger the XX injection happens when an application processes
Speaker 2: XML input from an untrusted source and its XML parser
Speaker 2: is configured insecurely. Specifically, it involves exploiting a feature of
Speaker 2: XML parsers that allows XML documents to declare and include
Speaker 2: external entities.
Speaker 1: External entities like pulling in data from outside the main
Speaker 1: XML file exactly.
Speaker 2: An attacker can craft malicious XML input that defines an
Speaker 2: external entity pointing to a sensitive resource like a local
Speaker 2: file on the server. If the parser is vulnerable, it
Speaker 2: might actually fetch and include the content of that file
Speaker 2: right into the XML document being processed.
Speaker 1: So they trick the parser into grabbing things it shouldn't like.
Speaker 1: What kind of things?
Speaker 2: Potentially, Yeah, this could allow them to view files from
Speaker 2: the server's file system. I think configuration files, password files
Speaker 2: like etc. Pass throught on Linux. It could also potentially
Speaker 2: let them interfere with back end systems the application talks to,
Speaker 2: or even low bunch attacks against other external systems from
Speaker 2: the application server itself. It exploits how some standard XML
Speaker 2: libraries handle these external entities, sometimes insecurely by default.
Speaker 1: So it's about tricking the XML parser into becoming an
Speaker 1: unwilling accomplice to fetch local files. Can you give a
Speaker 1: concrete example of what that malicious XML might look like?
Speaker 2: Sure, in a vulnerable app like utilidae or bupp, you
Speaker 2: might inject something like this into an XML input field
Speaker 2: doc typefood dot entity, xccsystem file dot ettc passwd barn
Speaker 2: xebar Okay. Breaking that down, the doc type part defines
Speaker 2: a new entity named XC. The system file dot icpasswd
Speaker 2: tells the parser that the content of this XCS entity
Speaker 2: is the content of the local file a setter pass.
Speaker 2: Then later in the XML n XS tries to use
Speaker 2: that entity, and.
Speaker 1: If the application is vulnerable.
Speaker 2: It will replace anx with the actual contents of the
Speaker 2: ETSETA pass file, and often that content will get reflected
Speaker 2: back in the applications response, letting the attacker see it.
Speaker 2: It's a direct way to leak sensitive server information.
Speaker 1: That's incredibly powerful access from just manipulating XML. How would
Speaker 1: you automate finding these and maybe grabbing specific config.
Speaker 2: Files For automation, you definitely turn to Burpsuite's Intruder tool again.
Speaker 2: You can load it up with a list of pre
Speaker 2: made XX payloads. There are great collections online like the
Speaker 2: payloads all the things repository on GitHub, and.
Speaker 1: Intruder tries all of them.
Speaker 2: Yeah, Intruder will systematically send requests with these different XXX payloads,
Speaker 2: targeting various parameters or parts of the XML input. It
Speaker 2: automates the fuzzing process trying different techniques to read local
Speaker 2: files like common config files, or interact with the system
Speaker 2: while you monitor the responses for any signs of success
Speaker 2: like leaked file contents appearing okay.
Speaker 1: Moving on to command injection vulnerabilities. The sounds well, pretty direct,
Speaker 1: like the attacker is literally typing commands. What's the danger
Speaker 1: level here?
Speaker 2: The danger level is extremely high critical, usually because these
Speaker 2: vulnerabilities allow an attacker to execute arbitrary operating system OS
Speaker 2: commands directly on the server that's hosting the web application.
Speaker 1: So if they get command injection.
Speaker 2: It's often game over. They can potentially compromise the entire application,
Speaker 2: steal or destroy all its data, maybe install malware, pivot
Speaker 2: to attack other internal systems, essentially take full control of
Speaker 2: the server infrastructure. It's one of those impactful vulnerabilities you
Speaker 2: can find.
Speaker 1: How is that different from something like say code injection.
Speaker 1: They sound similar.
Speaker 2: That's a really key distinction. OS. Command injection specifically runs
Speaker 2: commands at the operating system level, like LS to list
Speaker 2: files on Linux, or deeron Windows, or even rmaarf to
Speaker 2: wipe the disc. It's interacting directly with the server's.
Speaker 1: Shell, whereas code injection.
Speaker 2: Code injection executes attacker supplied code within the application's own
Speaker 2: programming language environment. So maybe injecting malicious PHP code that
Speaker 2: the PHP interpreter runs, or Java code or Python code.
Speaker 2: Both are extremely severe, but they operate at slightly different
Speaker 2: layers of the system stack.
Speaker 1: Got it, and how do attackers actually manage to sneak
Speaker 1: their OS commands in? How do they piggyback them onto
Speaker 1: legitimate input?
Speaker 2: They typically use command separators. These are special characters that
Speaker 2: the operating system shell understands as meaning run another command.
Speaker 2: Common ones on Linux Unix are the semi colon, pete mill,
Speaker 2: the ampersandic candor runs in background, double ampersand and L
Speaker 2: runs only if previous command succeeded. The pipe sends output
Speaker 2: of one command to another, and double pipe runs only
Speaker 2: if previous command failed.
Speaker 1: So they might append l's to some normal input exactly.
Speaker 2: For example, if an application has a feature to ping
Speaker 2: and IP address and takes the IP from user input,
Speaker 2: an attacker might provide one hundred point zero point zero
Speaker 2: point one LS. The application might build the command ping
Speaker 2: one to two point zero point zero point one LS,
Speaker 2: the OS runs, the ping finishes, sees the semi colon,
Speaker 2: and then just runs l's as a completely separate command.
Speaker 2: They're chaining commands together clever.
Speaker 1: So how would an ethical hacker discover this in a
Speaker 1: lab setting? What's the A.
Speaker 2: Common approach is using vulnerable features like maybe a DNS
Speaker 2: look up page in an app like mutilitay, combined with
Speaker 2: purp suites, repeater and intruder. You'd start experimenting in repeater,
Speaker 2: injecting potential command separators in simple OS commands after legitimate input,
Speaker 2: like trying eight point eight point eight point eight eight
Speaker 2: or eight eight point eight point eight in one one.
Speaker 1: Mean, just trying different separators and commands.
Speaker 2: Yeah, and then you'd use intruder to automate this fuzzing.
Speaker 2: You can provide lists of separators, commands, maybe even special
Speaker 2: fuzzing markers like sex sixcpres to systematically try different combinations.
Speaker 2: Then you carefully analyze the HTTP responses from the server
Speaker 2: looking for what in the response you're looking for the
Speaker 2: output of your injected commands. If you inject LS and
Speaker 2: suddenly see a file listing in the HTML response, or
Speaker 2: you injects and see user information like OD three to
Speaker 2: three WWW data, you know you've found a command injection vulnerability.
Speaker 2: You can use it to discover the OS type, running
Speaker 2: user installed software, all sorts of useful info.
Speaker 1: We've covered a lot of serious ground. Let's wrap up
Speaker 1: the vulnerability section with two big ones each, m MAL
Speaker 1: injection and sqel injection. First, HTML injection. How is this
Speaker 1: one characterized?
Speaker 2: HTML injection is often described as a rendering attack. It
Speaker 2: basically means an attacker can inject arbitrary HTML code tags
Speaker 2: like h one or imagy or even form into a
Speaker 2: web page, and that injected HTML gets rendered in display
Speaker 2: to other users.
Speaker 1: So it messes with how the page looks. What are
Speaker 1: the actual risks?
Speaker 2: Well? Compared to command injection, it might seem less risky
Speaker 2: for say, direct data theft, but it can seriously damage
Speaker 2: website's reputation by defacing its appearance. More critically, it can
Speaker 2: often be a stepping stone to more severe attacks. For instance,
Speaker 2: an attacker could inject a fake login form using HTML injection.
Speaker 2: That form might look legitimate, but it actually posts the
Speaker 2: user's credentials to the attacker server. Or they might inject
Speaker 2: HTML that helps them steal session cookies, potentially leading to
Speaker 2: a full cross site scripting EXSS attack if they can
Speaker 2: also inject script tags.
Speaker 1: So it's about manipulating what the user sees and potentially
Speaker 1: setting them up for something worse. How is it usually
Speaker 1: found and what's the defense.
Speaker 2: You can often find it manually in test apps, like
Speaker 2: maybe a stored blog page in bwapp. You try injecting
Speaker 2: simple HTML tags like btestp or maybe a small image
Speaker 2: tag and see if it actually renders on the page
Speaker 2: when you view it later and prevention. Prevention comes down
Speaker 2: to robust input sanitization. Again, any user supplied input that's
Speaker 2: going to be displayed back on a page needs to
Speaker 2: have potentially dangerous HTML characters properly escaped or stripped out
Speaker 2: before it's rendered. Using libraries designed for this is key. Also,
Speaker 2: implementing a strong content security policy or CSP is crucial.
Speaker 1: What does CSP do here?
Speaker 2: CSP tells the user's browser exactly what sources of content, scripts, images, styles, etc.
Speaker 2: Are allowed to be loaded and executed for your website.
Speaker 2: It can help mitigate the impact of injection attacks even
Speaker 2: if some malicious HTML or script manages to get through
Speaker 2: the initial sanitization right.
Speaker 1: And finally, the big one SQL injection or sequel sort
Speaker 1: of this, it sounds incredibly serious. What's the fundamental idea.
Speaker 2: It is extremely serious. Sequel is a web security vulnerability
Speaker 2: that allows an attacker to interfere with the database queries
Speaker 2: that an application makes. Essentially, the attacker crafts malicious input that,
Speaker 2: when included in a database query by the application, changes
Speaker 2: the query's logic in a way the attacker controls.
Speaker 1: You're basically talking directly to the database through the web
Speaker 1: application in effect.
Speaker 2: Yes, by manipulating the input, they trick the application into
Speaker 2: sending malicious sequel commands to the database on their.
Speaker 1: Behalf and potential impact If they succeed, what can they do? Oh?
Speaker 2: The consequences are typically catastrophic. Attackers can potentially read sensitive
Speaker 2: data from the database, the user credentials, personal information, credit
Speaker 2: card numbers. They can modify or delete data. They can
Speaker 2: often bypass authentication mechanisms entirely, maybe gaining administrative access to
Speaker 2: the application.
Speaker 1: Can it get worse than that?
Speaker 2: Yes, Depending on the database configuration and permission, they might
Speaker 2: even be able to execute operating system commands on the
Speaker 2: database server itself, completely compromising the underlying infrastructure, or launch
Speaker 2: denial of service attacks that bring down the database and
Speaker 2: the application. It's a gateway to the Crown jewels usually Wow.
Speaker 1: You mentioned bypassing authentication. Can you give an example of
Speaker 1: how that works? It sounds almost too simple, It.
Speaker 2: Often is surprisingly simple with basic vulnerabilities. Let's say you
Speaker 2: have a log in form that takes a username in password.
Speaker 2: A vulnerable application might build a SQL query like select
Speaker 2: from users where a username improtucer and password.
Speaker 1: Okay, standard log in query.
Speaker 2: Now, an attacker might enter something like R one one
Speaker 2: into the username field and maybe anything in the password field.
Speaker 2: The application might then construct the query select from users
Speaker 2: where username or one in password or whatever.
Speaker 1: What does the R one one do?
Speaker 2: Well? One one is always true, so the wear clause
Speaker 2: becomes where username equal true. Since anything or true is
Speaker 2: always true, the condition matches every row in the user's table.
Speaker 2: The at the end is a comment signal and SQL
Speaker 2: often making the database ignore the rest of the line,
Speaker 2: including the password.
Speaker 1: Check, so the query just returns all users exactly.
Speaker 2: And often the application code will just log in the
Speaker 2: first user returned by the query, which is frequently the
Speaker 2: administrator account. Boom, They're logged in as admin without needing
Speaker 2: a password. It's the digital equivalent of a skeleton key.
Speaker 1: That's incredibly effective for such a simple input. Now, beyond
Speaker 1: logging in, how do attackers use SQL to explore the
Speaker 1: database and steal data? You mentioned a tool called school map.
Speaker 2: Right once you've confirmed in SQL injection, point maybe using
Speaker 2: burp suite to find where input affects the database. School
Speaker 2: Map is the go to tool for automating the exploitation. It's
Speaker 2: incredibly powerful and comes pre installed with Cali Linux.
Speaker 1: How does it work? What can it do?
Speaker 2: You can basically feed school Map a saved AGTTP request
Speaker 2: from burpsuite that contains the vulnerable parameter using the alve flag.
Speaker 2: Then you give it commands. It can automatically figure out
Speaker 2: what type of database is on the back end my SQL,
Speaker 2: Microsoft's server, Postgrescool, Oracle, et cetera, often by fingerprinting the
Speaker 2: responses or grabbing the database.
Speaker 1: Banner so it identifies a target first. Then what Then you.
Speaker 2: Can tell it to list all the databases available you Wise,
Speaker 2: once you pick a database of interest, say one name
Speaker 2: Noah SIP, you can list all the tables within that
Speaker 2: database no aspit tables and.
Speaker 1: Find interesting tables like credit cards exactly.
Speaker 2: Once you find an interesting table like credit cards, you
Speaker 2: can list all the columns within that table dat d no,
Speaker 2: ask betty t credit cards columns to see what kind
Speaker 2: of data it holds, maybe CC number or CCVE expire date, and.
Speaker 1: The final step getting the actual data yep.
Speaker 2: The final step is to tell school map to dump
Speaker 2: all the data from that specific table DATCHI knee no
Speaker 2: OSC datchnee credit cards dump. It will then use various
Speaker 2: SEQL injection techniques to extract every row and column from
Speaker 2: that table and display it right there for you. It
Speaker 2: automates what would be an incredibly tedious manual process potentially
Speaker 2: revealing highly sensitive information. It's an ethical hacker's best friend
Speaker 2: when it comes to exploring databases via seqel.
Speaker 3: Wow, that is incredibly comprehensive, going from finding a small
Speaker 3: flaw to potentially dumping the entire database. What an eye
Speaker 3: opening journey through just some of these web vulnerabilities and
Speaker 3: the tools used to find them. It really hammers home
Speaker 3: how many potential cracks there can be in the digital
Speaker 3: foundations we rely on constantly.
Speaker 2: It truly is a dynamic field, isn't it. It's constantly
Speaker 2: evolving the world of web security and bug bounty hunting specifically.
Speaker 2: It just demands continuous learning. You have to keep up
Speaker 2: with research adapt quickly. New threats, new vulnerability types, new
Speaker 2: attack techniques emerge all the.
Speaker 1: Time, so what worked yesterday might not be enough today exactly.
Speaker 2: Success in this area really comes from well, a deep curiosity,
Speaker 2: maybe even a bit of obsession, and definitely persistence in determination.
Speaker 2: You have to be willing to dig deep and always
Speaker 2: try to stay one step ahead.
Speaker 1: So a final thought for our listeners, then, in this
Speaker 1: world of ever evolving digital threats, how much do you
Speaker 1: really know about the hidden weaknesses and the websites and
Speaker 1: applications you interact with every single day?
Speaker 2: And maybe what might that knowledge compel you to explore
Speaker 2: next