OWASP Top 10

Note: In this section our example will be taken using OWASP Juice shop which is a voluntarily vulnerable application. You can get it here along with explainations on how to install and run it on Kali (For the example the install was made using Docker and for challenges not available with docker I used the one from tryhackme here) We are also going to use examples from XSS Game
To go further with juice shop check out the gitbook here

SQL Injection

Source: Practical Ethical Hacking - TCM Security

To find a SQL injection we can try to add special chars in forms and analyze the responses we get.
In our example when using a special char in the login form we got a very verbose sqlite error that indicates that we have sql injection
Using this payload test' OR 1=1;-- we were able to login because -- comments the rest of the query so the password is not checked

Defenses again SQLi

Source: PEH - TCM Security Academy

Broken authentication

OWASP A2-Broken Authentication
In our example we have user enumeration
- When a user exist if we go to forgot password we can get a security question
- If the user does not exist we do not get a security question
We also have to see if we can bypass authentication

Sensitive data exposure

OWASP A3-Sensetive Data Exposure
Using directory busting we can find sensitive info like folders or backup files
- In our example there is an ftp page
We can check the response and grep on keywords like passwords or keys
We also need to check if HSTS is enabled which means that we need to check if the strict transport security header is used and properly set up. Check this on OWASP for more info.
It is also checking SSL we can use testssl for this purpose or nmap with nmap --script=ssl-enum-ciphers -p 443 domain.com

XML External Entities (XXE)

In this XML code we are defining something that works like a constant in a way, everytime we will call the &from; we will put the value "someone".
However when using this we could mess up with it by adding special chars that would be interpreted as xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE gift [
  <!ENTITY from "someone">
]>
<gift>
  <To>someone else</To>
  <From>&from;</From>
  <Item>A nice item</Item>
</gift>

We can try this payload taken from PayloadsAllTheThings(https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/XXE%20Injection/README.md#classic-xxe)

<?xml version="1.0" encoding="ISO-8859-1"?>
  <!DOCTYPE foo [  
  <!ELEMENT foo ANY >
  <!ENTITY xxe SYSTEM "file:///etc/passwd" >]><foo>&xxe;</foo>

For our example we put this in a file called test.xml
We will abuse this file upload function
We select our xml file to upload it and enter some string in the description field and send this
It works we are able to get the /etc/passwd file

Broken Access Control

OWASP A5-Broken Access Control
It means that a user gets access to something they should not be able to access
In our example we are going to use the customer feedback section and leave a feedback as another customer.
There is a hidden userID field on the form that we can see if we check out the source code
If we make it visible we can see our own user id is 21
We can change it to 1 for example
If we submit this we have successfully exploited Broken Access Control by posing feedback as another user

Security Misconfiguration

OWASP A6-Security Misconfigurations
Default credentials in a login page
Stack traces

Cross Site Scripting

OWASP A7-Cross Site Scripting
DOM Based XSS
XSS Game
To find an XSS the thing to do is to look for inputs in the website like search bar, comment form, etc.
Goals: steal cookies, deface website, denial of service, keylogging, ...

Reflected

Our XSS is not persistent so our payload is not kept in database
In our example we stumble on an interesting url that takes an id parameter:
We can try to inject our payload <iframe src="javascript:alert(xss)">

Stored

Our XSS is persistent so our payload is stored in the database so anyone accessing our page will have the payload executed.
For this example we are going to use XSS game and this payload <img src='#' onerror=alert(1) />
It works