Advanced Traffic Pivoting with Netcat

Background - Many a times during a pentest, I need to access machines on an internal network that are not reachable from outside, since they lie in the private ip space. So the solution is to setup the previously 0wned box on the DMZ to pivot...

A Case of Polluting HTTP Parameters

Hey Guys

Recently a friend came to me and told me about a scenario which he had used to deploy his web application. He had built his application using PHP on Apache. There was a front-end server directly accessible to the internet and a back-end server only accessible to the front-end server. The PHP application deployed on the front end server included PHP files kept on the back-end server and showed it on the browser. The included PHP files were hard coded in the code of the PHP application running on the front-end server and this front end application took a GET parameter as input.

Now, this scenario kind of caught my interest. I recently read about HTTP parameter pollution and I thought this attack might work in this case. So I began digging and experimenting. And I came up with a demonstration which shows how will this attack work when someone is using a setup similar to the setup described above to bypass a hard coded value in the code. I know this is not recon stuff ,but still its interesting.. 😉

We will see 4 PHP codes here :-

1.) hpp.php – The main application deployed on the front-end server, which remotely includes a PHP code (cms.php) kept on the back-end server.

2.) cms.php – A PHP code kept on the back-end server which receives an input from hpp.php in the “function” parameter and includes a PHP code (set to normaluser.php) meant for a normal user locally.

3.) normaluser.php – A PHP code kept on the back-end server meant for a normal user and included by cms.php .The ping command was set in this case to show that the normal user can only use the ping service.

4.) adminuser.php – A PHP code meant for an admin user. This code can run any OS command directly to show that this code really is for the admin 😉 .

Second Order SQL Injection

Second Order SQL Injection :-

I always thought that escaping single quotes in a string based user input used for database transactions will prevent SQL injections..but this is not always the case when single quotes are escaped inconsistently (as we will see in this blog).

Say hello to SQL injection of the second order !
Basically second order SQL injections take place when one functionality of a web application takes a user input from a user, escapes (not strips) all SQL metacharacters and inserts that data input into a database. Next, some other functionality of the same application uses that data to craft another SQL query to do a database transaction without escaping that data first (bad idea!). The database transaction done by the second functionality introduces a SQL injection bug in the web application known as second order SQL injection.

I have’nt heard of any Second Order SQL Injection Attacks on real world targets, so decided to make up an example attack myself. Following are the two functionalities with their respective codes (select.php and insert2.php).

 The first functionality inserts data into the database. The second functionality uses the data inserted into the fname column to craft a SQL query and get data from the database and show it on the frontend. For making it easy to understand, all the SQL queries run by the web applications are also shown on the frontend.

Antivirus Evasion with Metasploit Pro

Introduction AV Evasion has always been a topic of interest among security researchers as well as malware writers. Though less talked about, AV Evasion for a Penetration Tester too has paramount importance. For instance if you were to conduct a penetration test, you would want to...

Pentesting Networks for weak passwords using Metasploit

Basic Test Using Metasploit Penetration Testing Tool

In the previous post on metasploit, we did a basic penetration test of a network using the WebUI of Metasploit. In this post we will see how metasploit can help us in identifying systems in a network that do not follow a strong password policy. Basically, we are going to use the scan and bruteforce option of Metasploit WebUI to accomplish this task.

First we complete the project creation process.

       

 

Now we click on the scan option of the discovery module and fill in all the project related settings.

Session Hijacking

Overview:-

“Session Hijacking attack consists of the exploitation of the web session control mechanism, which is normally managed for a session token. Because http communication uses many different TCP connections, the web server needs a method to recognize every user’s connections. The most useful method depends on a token that the Web Server sends to the client browser after a successful client authentication. A session token is normally composed of a string of variable width and it could be used in different ways, like in the URL, in the header of the http requisition as a cookie, in other parts of the header of the http request, or yet in the body of the http requisition.

The Session Hijacking attack compromises the session token by stealing or predicting a valid session token to gain unauthorized access to the authenticated parts of a web application.” – (https://www.owasp.org/index.php/Session_hijacking_attack)

The following figure shows a normal web application login page. Using this login page a normal user as well as an admin user can log into the application.

The following figures show the menu screen that is shown to the normal user or the admin user after they log in.