Author: kanishka10

Hello, aspiring ethical hackers. In one of our previous blogposts, you learnt what is command injection, types of command injection etc. In this blogpost, you will learn about Commix, a tool that is used to automatically exploit command injection vulnerability.

Commix, which is short for (comm) and (injection) e(x)ploiter is an open source pen testing tool written by Anastasior Stasinopolos that is useful in automatically detecting and exploiting command injection vulnerabilities. Written in Python, commix can be installed on any platform that supports Python.

On pen testing distros like Kali Linux, commix is installed by default. So, we will be using it for this tutorial. As target, we will be using mutillidae in Metasploitable 2. Mutillidae, is an intentionally vulnerable web application for practicing ethical hacking. See how to install Metasploitable 2 in virtualBox and set up a virtual hacking lab.

A webpage “dns-lookup.php” in mutillidae has a command injection vulnerability in the Hostname/IP field. These vulnerabilities can be detected using web vulnerability scanners like OWASP ZAP (aka zaproxy), Nikto, Burpsuite etc.

What this webpage does is when you provide an IP or hostname, it performs a DNS lookup of that IP or hostname (For example, we have used it on google.com).

This is its name functioning but when you join another command to the IP/hostname using ampersand as shown below, it also executes that command as shown below.

Commix allows us to exploit this vulnerability automatically. To do this, with commix, we need information about the parameter being sent while sending this query. This can be achieved by using OWASP ZAP as an intercepting proxy. See how to set OWASP ZAP as an intercepting proxy.

The target can be specified in commix using the “-u” option and POST data can be specified using “–data” option as shown below.

When you execute this command, commix will prompt you to set cookies. Cookies are not needed in this case.

Then, commix says the parameters we are testing is vulnerable to command injection and it will prompt you for a pseudo-terminal access.

Selecting ‘Yes” will give us access to the commix shell a shown below.

Apart from giving you a terminal on the target system, commix provides a lot of enumeration options. Let’s see some of them here.

–hostname

It retrieves the hostname of the target system.

–current-user

This command retrieves the current user on the target system.

–is-root

This command checks if the current user has root privileges.

–is-admin

This command checks if the current user has admin privileges.

–sys-info

As you might have guessed by now, this command retrieves the system information of the target.

–users

This command retrieves all the users on the target system.

–passwords

This command retrieves passwords of all the users on the system.

Here, of course we did not get any password hashes, as we do not have enough privileges to get those.

–privileges

This command retrieves the privileges of all the users on the target system.

–ps-version

This command retrieves the version of the PowerShell installed on the target system.

–all

Instead of enumerating each item separately, you can retrieve all the information from the target system using the “–all” option.

–os-cmd

This command is used to execute a single operating system command on the target system. For example, let’s execute “ls” command on the target system.

–os=

This command is used to force the backend operating system (For example, Windows or UNIX.

Hello, aspiring ethical hackers. In one of our previous blogposts, you learnt what XSS vulnerability is, what are the different types of XSS vulnerabilities and its impact on web security. Wouldn’t it be good if there was a tool that can automatically detect and exploit XSS vulnerabilities? In this blogpost, you will be learning about one such tool named XSSer which is an automatic framework to detect, exploit and report XSS vulnerabilities in web applications.

XSSer is a python script and can be installed on all Linux systems with python installed. It is installed by default in Kali Linux and we are going to use the same for this tutorial. See how to install kali Linux in virtual Box. We will be using Mutillidae in Metasploitable 2 as target to test with XSSer as it is easily available to download and this tutorial is easily reproducible. See how to install Metasploitable 2 in VirtualBox.

Mutillidae is a vulnerable web app that intentionally consists of all OWASP 10 vulnerabilities for practicing web application hacking. Also see how to create a virtual hacking lab in virtual Box. In the page shown below belonging to Mutillidae, the blog entry field consists of a XSS vulnerability. These vulnerable pages can be detected using web vulnerability scanners like OWASP ZAP aka Zaproxy, Nikto and Burpsuite etc.

XSSer can also be used to scan for XSS vulnerabilities using the “–all” option” as shown below.

However, here XSSer failed to find any XSS vulnerability. Let’s see how to find any XSS vulnerability in this specific section. For this, I start OWASP ZAP as intercepting proxy to capture web requests. Then, I change the setting in the browser to access the web through this proxy and visit the vulnerable page again on this browser.

I type “This is a new blogpost” in the blogpost entry and save the blogpost. Now, when we view the captured web request in OWASP ZAP as shown below, we can see the request being sent to the target.

Now, we copy the highlighted data above and use it in our XSSer tool. The only difference is to find out the XSS vulnerability, we add text “XSS” in the place of any vector that us vulnerable to XSS.

Note the method the query is using to pass this data. There are two methods by which data is sent and received: GET and POST. XSSer has an option to use both the methods: (-g) for GET method and (-p) for POST method. OWASP ZAP has shown us that this data is being passed using the POST method. So, we will be using the same with XSSer.

Now, you can see that vector “blog_entry” is vulnerable to cross site scripting using URL method. Here, we tried one vector. XSSer provides an option to inject a list of vectors provided by XSSer. To test all these vectors, we can use the “—auto” option. XSSer in total has 1291 injection vectors.

As you can see, XSSer found 1287 of 1291 injection vectors in the web app. XSSer also has the option of using payloads. Here the payload can be anything even the most popular <script> alert (“HC”)</script). Here is how we specify the payload in XSSer.

Here I have given the same above-mentioned script as payload.

Specify your own payload

Using the “-Fp” option, you can even specify your own payload for final injection.

Execute payload remotely

The “-Fr” option is used to execute the payload remotely.