辅导案例-FIT 2093-Assignment 2

Monash University

FIT 2093 Introduction to Cyber Security
Assignment 2: Web Hacking Challenge

In this assignment, your goal is to do security testing of a mini web application to try find vulnerabilities
in it using techniques covered in our Web security lecture, and exploit them to break the app’s security.
You can access the web application at the following URL:

http://13.54.173.115/brokenapp.php

This web app give access to registered members of a `Broken App’ group to access some information
common to the group members (provided using the PHP server script at brokenapp.php) as well as
personal private information for each group member (via the script at brokenapp-personal.php
on the same domain).

Visit the web application URL above using your web browser. If all is well, the browser should display
a page that looks like this:



Tasks. Your task is to perform the following security tests on this web application.

Part A: Personal Private Information Security Test

In this part, your aim is to do security testing of the personal private information part of the web app.
For this, you are given member 1’s password, namely:

Ro4mvSemq45xfepvaEr24



(1) Here, we consider an attack against member 1 by some outsider (non-member) attacker. Try
logging in with the given member 1 password, and examining that member’s private information.
Based on the application behavior, where on this page could there be a possible point where a
reflected XSS vulnerability might exist? Why? Perform a test to see if an XSS vulnerability exists
for an attack against member 1, and explain your test, its results, and conclusion on why/why not
such a vulnerability exists and can be exploited. (1 mark)

(2) Test the application against an attacker who is one of the authorized group members, in particular
the member with ID number 1. Can that member gain unauthorized access to another member’s
personal private data? If so, explain the vulnerability you found and how member 1 can exploit
it, show any private member data exposed by the attack, and briefly explain how the vulnerability
could be eliminated. In any case, explain the tests you did, the results, and your interpretation of
them. (2 marks)



Part B: Shared Group Private Information Security Test

In this part, your aim is to do security testing of the shared group private information part of the web
application, from the point of view of an outsider (non-member) attacker trying to reveal the group
private information. Although you are not given the shared group password, you are given the php code
for the relevant script brokenapp.php (available for download on Moodle).

(3) Look at the details in the brokenapp.php PHP script available on Moodle to see how user
input is read in from the user's browser request and how the authentication check is performed.
You should read the PHP documentation on the PHP functions used in the script, see
http://php.net/manual/en/ and search for the relevant functions. The shared group password,
whose cryptographic hash is hard-coded in the script, was generated using the php function call
password_hash(pwd, PASSWORD_DEFAULT),where pwd is the password to be hashed
(note that the hash includes also a salt value generated at random). To help your security tests,
you are also given a simple PHP script called password_hasher.php (the code is available
on Moodle, it can be run by pointing your browser to http://13.54.173.115/password_hasher.php ;
alternatively, you could run it by copying it into the web server folder /var/www/html/ of
your FIT2093 Ubuntu-64 VM and then pointing your VM Firefox browser to
http://localhost/password_hasher.php ). The script takes an input password from a user and
displays its hash value (generated using the php function call above) when the user clicks the
small button below the text box.

Using the above information/tools, attempt to identify a vulnerability in brokenapp.php. If
you found a vulnerability, explain how it can be exploited, provide any secret information
revealed, and briefly explain how the brokenapp.php code could be modified to eliminate
this vulnerability. In any case, explain what tests you did, the results, and your interpretation of
them. (2 marks)


Note: You should assume the attacker will NOT have any network eavesdropping/modification access
(the current web application under test is running on an unencrypted http connection, but to protect
against network eavesdropping/modification will be implemented over an encrypted https connection in
the final production version).

Submission

Submit a report consisting of your answers to tasks (1), (2), (3). You may include screen shots and any
code used to solve each part of the task. The page limit for the report is 5 pages.

Upload the file in PDF format on Moodle by 11:59pm GMT, Sunday 21 June, 2020.

The 5 marks full grade allocated for this assignment will be distributed among the tasks as indicated
above. For each of those tasks, 80% of the marks will be based on correctness of the vulnerability
identification and/or exploitation technique (as appropriate) and the remaining 20% to the written answer
editorial quality (clarity, accuracy, style).

IMPORTANT: This is an INDIVIDUAL assignment for students to complete on their own. You MUST
NOT work with any other student (or person) on this assignment.



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