Skip to main content

Cross Site SQL Injection (XSSQLI)

While going through a nice paper written by Cesar Cerrudo on 'Hacking Intranet with IE', I found an interesting term XSSQLI. Though it's not a new vulnerability,it's a combination of two attacks. Details:
XSSQLI is a term to describe a Cross Site Request Forgery (XSRF) + SQL Injection attack. This
attack consists in forcing a user to request a web application URL that will exploit a SQL
Injection vulnerability, as XSRF attacks the user can be forced to request a URL by using a
img src="”http://intranetsite/pagevulnerable?id="';"

When a victim browses a web page with the above HTML code an automatic request will be
made to “intranetsite” web application without the user noticing it. The difference with a classic
XSRF attack is that instead of the URL requested triggering some action in the target web
application it will exploit SQL Injection.

Within Intranets, some web applications implementations use Windows integrated authentication, this means that the user authenticates to the web application with his Windows credentials, which is done automatically by IE because of “Automatic logon only in Intranet zone” security setting. MS SQL Server (other DBMS could be attacked in this way too) also authenticate users with Windows integrated authentication, some web applications are configured to access SQL Server backend database authenticating with the current Windows user that's accessing the web application. If an
attacker exploits a SQL Injection vulnerability in this kind of web application isn't as valuable as other attack paths since the attacker could directly connect to SQL Server and run SQL statements as far his permissions allows him but by using XSSQLI in order to attack, for instance a SQL Server DBA, the attacker will be able to elevate privileges running SQL Server statements with DBA permissions.



Popular posts from this blog

Ardilla- New tool for finding SQL Injection and XSS

Three Researchers -- MIT's Adam Kiezun , Stanford's Philip Guo , and Syracuse University's Karthick Jayaraman -- has developed a new tool ' Ardilla ' that automatically finds and exploits SQL injection and cross-site scripting vulnerabilities in Web applications. It creates inputs that pinpoint bugs in Web applications and then generates SQL injection and XSS attacks. But for now Ardilla is for PHP -based Web app only. The researchers say Ardilla found 68 never-before found vulnerabilities in five different PHP applications using the tool -- 23 SQL injection and 45 XSS flaws. More information is awaited. For their attack generation techniques refer to their document at:

Combining power of Fiddler with Burp

Both are pretty powerful tools when it comes to intercept and modify http communications. But at some point of time, they become even more powerful combo if tied with each other. They complement each other. In a recent pentest I came across a similar situation where in Burp was not able to intercept a specific kind of traffic and Fiddler came to rescue. The application was designed to upload video. The initial communication was straight forward, I mean logging into application, filling up the video details etc. And all these were easily captured by Burp except the point where you hit the Upload Video and it connects to a different server and surprisingly it was not captured by Burp, not sure why, even after repeated attempts. So, I fired Fiddler to see if the it sees this request. But it's a;ways to play with requests using Burp due to it's various functionalities like, Intruder, Repeaters etc. But it was necessary to capture this request in Burp. So the below steps can be

File Upload through Null Byte Injection

Sometimes, during file upload we come across situation wherein there would be check on the file extension at the client side as well as server side too. If the application does allow only .jpeg extension to be uploaded, the client side java script checks for the extension of the file before passing the request. We all know that how easily this can be defeated. Some applications, checks for the extension at the server side also. That's not easy to bypass. However there are some ways with which it still can be bypassed. Most of server side scripts are written in high level languages such as Php, Java etc who still use some C/C++ libraries to read the file name and contents. That leads to the problem. In C/C++ a line ends with /00 or which is called Null Byte. So whenever the interpreter sees a null byte at the end of the a string, it stops reading thinking it has reached at the end of the string. This can be used for the bypass. It works for many servers, specially php servers. T