User audit: Difference between revisions

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[[File:User-audit-task.PNG|thumb|User audit task]]
[[File:User-audit-flag.PNG|thumb|User audit flag and url parameters]]
===Description===
===Description===
Junior system administrator has a recurring task to do regular audit on users and administrators present on the server.
Junior system administrator has a recurring task to do regular audit on users and administrators present on the server.
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===Solution===
===Solution===
When I opened the web page, I noticed that the links open txt files on the web page and the parameters are sent with the GET command. This is shown in the browser address bar.
When I opened the web page, I noticed that the links open txt files on the web page and the parameters are sent with the GET command. This is shown in the browser address bar.
I immediately set off to see how the program would work if I used the ../ command to navigate the folder. After testing for a while, I found that with proper configuration, we can open the entire server file structure in this way.
 
I immediately set off to see how the program would work if I used the ../ command to navigate the folder. After testing for a while, I found that with the right formatting of the address parameter we can also open files outside the www folder from the server.


So I opened the secret.txt file by adding <code>../../../backup/secret.txt</code> to the address field
So I opened the secret.txt file by adding <code>../../../backup/secret.txt</code> to the address field

Latest revision as of 11:36, 30 September 2022

User audit task
User audit flag and url parameters

Description

Junior system administrator has a recurring task to do regular audit on users and administrators present on the server.

He has created a web application to help him with the task.

50pts

Question

Use the weakness in the web application to read a secret file at /var/backup/secret.txt

Solution

When I opened the web page, I noticed that the links open txt files on the web page and the parameters are sent with the GET command. This is shown in the browser address bar.

I immediately set off to see how the program would work if I used the ../ command to navigate the folder. After testing for a while, I found that with the right formatting of the address parameter we can also open files outside the www folder from the server.

So I opened the secret.txt file by adding ../../../backup/secret.txt to the address field

This also gave me the ticket.

Tools

  • Firefox / Browser

Flag

ctftech{file-included}