Moreover, you can ask for more time by sending am email (body can be empty) with

the subject “ECM2426  CA:  Please  check  VM  time” to [email protected]. The dead- line for such requests is the last Tuesday before the submission deadline, precisely:

2023-12-05T17:59:59 GMT

After this deadline, request will be processed on a “best effort”-basis, but there is no guarantee that they are processed before the submission deadline.

Referencing and Academic Conduct

This is an individual assessment. Hence, you are not allowed to discuss solutions of this course work, or concrete instructions how to obtain solutions, with others. This includes discussions on WhatsApp groups or posting questions on Stack Overflow. The univer- sity requires you to cite the work of others used in your solution and to include a list of references. You must avoid plagiarism, collusion and any academic misconduct be- haviours. For further information and guidance, please take the self-learning “Academic Honesty and Plagiarism” .

Furthermore, you need to work on the VM assigned to you.  Not following this rule, will also consider as academic misconduct.

Marking Scheme

The marks for the individual questions are denoted for each (sub)-question. In addition, please note:

• You need to work on the VM assigned to you and only to you. Some tasks result in solutions that are unique to your VM. Hence, solutions obtained on a different VM will result in zero marks.

• Your submission needs to follow a specific format, detailed in the next section. Not following this format will result in zero marks. As part of the VM, a script is sup- plied that does provide a basic check of the required format. You are encouraged to make use of this script. If this script cannot recognise your solution/submission, it will likely result in zero marks.

Submission

The submission consists only out of one spreadsheet in OpenDocument format ( .ods). This file format is, for example, supported by LibreOffice (https://www.libreoffice. org/), which is installed on the provided VM. The VM also provides a template of the spreadsheet, named 2023-ecm2426-ca-.ods (the  part will be replaced by a unique identifier) in the home directory of the user lh in a folder coursework, i.e., /home/lh/coursework.

For each sub-question, you will need to fill out a clearly marked field in the column B of the provided spreadsheet.  If you want to declare the use of specific references,

you can do this in column D. Please do not change the UUID in the last row of the spreadsheet.

The VM contains a tool check-submission that you can use to check the validity of your created zip file. It is strongly recommended that you use this tool to check the compliance of your spreadsheet to the required submission format, before submitting your solutions:

lh@ML-RefVm-326614:~$ check-submission  2023-ecm2426-ca-.ods

This script will check the syntactic compliance of your submission, i.e., there is a so- lution for each question. It does not check for the correctness of your submission. Note that a successful run of the check-submission script does neither guarantee that your submission is complete nor that it follows the guidelines. Checking that the submission is complete and that the individual entries comply to the specified format is your responsi- bility!

You can copy the spreadsheet to your local machine using scp or sftp.  Note that also for scp (and sftp), you need to configure the correct port. Assuming that you can connect to the VM using the following command:

achim@logicalhacking:~$ ssh  -p  65042  [email protected]

You can use (note the scp using an uppercase P for specifying the remote port):

achim@logicalhacking:~$ scp  -P  65042  [email protected]:coursework/2023- ecm2426-ca-.ods  .

to copy the spreadsheet to your local machine. Of course, you can also use a graphical

front-end, as, e.g., provided by putty or winscp.

Some question might refer to files provided on the VMin a folder /home/lh/coursework .  If you accidentally delete or modify a file, there is a read-only backup available in the hidden directory /home/lh/.coursework (note that the directory starts with a ‘.’ and, therefore is only shown when doing an ls  -a).

1  Foundations & Access Control

Exercise 1                                                                                                              (20 marks)

The virtual machine 2023-ecm2426-ca has several regular user accounts configured. In this exercise, you should explore these accounts and their access rights.

E.1.1. (5 marks):   List all logins (not the full usernames) that both have numerical user id larger or equal than 2000 and that are a member of the group staff.

Submit your answer in cell B2, separate the logins with a comma, e.g., “joe, jane, root

E.1.2. (5 marks):  Analyse the VM to obtain the password of the user with the numer- ical user id 2000.  Note that you should obtain the password using reconnaissance, not by running a computational expensive password cracking tool.

Submit your answer in cell B3 of the spreadsheet.

E.1.3. (5 marks):  The user with the numerical user id 2001 has a file flag in their home directory. What is the content of this file?

Submit your answer in cell B4 of the spreadsheet.

E.1.4. (5 marks):  List all users with their login that can access the content of the file flag in the home directory of the user with the numerical id 2001.

Submit your answer in cell B5 of the spreadsheet, separate the logins with a comma, e.g., “joe,  jane,  root

2 Cryptography, Signatures & PKIs

Exercise 2 (15 marks)

In the home directory of the user lh there is an X.509 certificate stored in a file called /home/lh/coursework/exercise02/cert.pem. This certificate should be used for secur- ing a web server. The directory also contains an asymmetric key pair, stored in the file key.pem and an encrypted file secret.txt.enc.  There is no password set on this key pair.

For this excercise, you might want to use the openssl command line tool, which is provided on the virtual machine.

E.2.1. (2 marks):  Name the signature algorithm that has been used for signing the cer- tificate.

Submit your answer in cell B6 of the spreadsheet.

E.2.2. (2 marks):  Name key length used by the signature algorithm that has been used for signing the certificate.

Submit your answer in cell B7 of the spreadsheet.

E.2.3. (3 marks):  Is the certificate valid for the domain www1.exeter.ac.uk?

Submit your answer in cell B8 of the spreadsheet.

E.2.4. (3 marks):  Is the certificate valid for the domain www3.exeter.ac.uk?

Submit your answer in cell B9 of the spreadsheet.

E.2.5. (5 marks):  Decrypt the file secret.txt.enc. What it is content?

Submit your answer in cell B10 of the spreadsheet.

3 Security Protocols

Exercise 3 (15 marks)

The provided VMallows you to access a network that uses the IP range 172.17.0.* and your virtual machine is connected to this network via the network interface docker0. This network contains a number of computers that might have insecure services installed.

As user lh, analyse the network traffic on the 172.17.0.* (e.g., using Wireshark) and answer the following questions related to the http session:

E.3.1. (5 marks):  Give the full URI of the password protected web area accessed in this session.

Submit your answer in cell B11 of the spreadsheet.

E.3.2. (5 marks):  Give the username of the user who is successfully accessing the pro- tected web area successfully.

Submit your answer in cell B12 of the spreadsheet.

E.3.3. (5 marks):  Give the (cleartext) password of the user accessing the protected area. Note that no computational expensive techniques (e.g., a brute-force attack on a password hash) are required.

Submit your answer in cell B13 of the spreadsheet.

4 Formal Analysis of Security Protocols

Exercise 4                                                                                                                (15 marks)

The file /home/lh/coursework/exercise04/ecm2426.AnB contains a (incomplete) secu- rity protocol specification in Alice&Bob notation.  The specification is incomplete, as it lacks one fact of the initial knowledge (denoted by ). Moreover, the last protocol step, that is required to complete the protocol securely, is missing. Answer the following questions with the help of ofmc.

E.4.1 (5 marks):   One role has an incomplete initial knowledge, denoted by  in the provided specification.  Replace with the minimal fact that is required so that the protocol is executable.

Submit your answer in cell B14 of the spreadsheet.

E.4.2 (2 marks):   Who needs to send the last message required to complete the proto- col securely?

Submit your answer in cell B15 of the spreadsheet.

E.4.3 (3 marks):   Who receives the last message required to complete the protocol se- curely?

Submit your answer in cell B16 of the spreadsheet.

E.4.4 (5 marks):   What message needs to be exchanged in the last protocol step that is required to complete the protocol securely?

Submit your answer in cell B17 of the spreadsheet.

Important Note: Due to a bug in the setup script for the VMs, in some instances the initial knowledge of the roles specified in /home/lh/coursework/exercise04/ecm2426 . AnB lacks the roles themselves.  If this is the case, please add them in addition to the denoted missing . For example, if your protocol specification includes

Knowledge :

A:  pk(A),  g;

B:  pk(C),  ,  h

then please change it to:

Knowledge :

A:  A,  B,  pk(A),  g;

B:  A,  B,  pk(C),  ,  h

5 (Manual) Dynamic Security Testing

Exercise 5 (20 marks)

The VM has a small Message Board application installed that allows people to post (en- crypted) messages. It can be accessed at http://127.0.0.1:5000, using a web browser that runs on the VM.

The user lh can use sudo to start/stop the application:

lh@ML-RefVm-326614:~$ sudo  systemctl  start  message-board

lh@ML-RefVm-326614:~$ sudo  systemctl  stop  message-board

During the start of the application, the database is reset to an empty state. Note that

also during a system restart, the database state is reset.

Assume you are a penetration tester tasked to analyse this application.  You should test the application for Cross-Site Scripting (XSS) and SQL Injection (SQLi) vulnerabilities. In particular, you should find:

•  One SQL Injection (SQLi) vulnerability that allows you to access a post that other- wise is not accessible.

E5.1. (5 marks):   What is the full URL used for exploiting the vulnerability? Submit your answer in cell B18 of the spreadsheet.

E5.2. (5 marks):  What is the content of this “secret” message?

Submit your answer in cell B19 of the spreadsheet.

• One XSS vulnerability that allows you to access a session cookie.

E5.3. (5 marks):  What is the full URL used for exploiting the vulnerability? Submit your answer in cell B20 of the spreadsheet.

E5.4. (5 marks):  What is the content of the session cookie?

Submit your answer in cell B21 of the spreadsheet.

6 Static Security Testing

Exercise 6 Static Analysis (15 marks)

In the directory /home/lh/coursework/exercise05/message-board/ there is copy of a version (not necessarily the one that you analysed in the last exercise) of a message board application.  Analyse the application using the static security scanner “bandit” (https://github.com/PyCQA/bandit).  The bandit tool is part of the provided VM and the version installed on the VM will be used as a reference for assessing your solution.

You can run bandit as follows, and it should report three potential security issues:

achim@logicalhacking:~/coursework/exercise06/$ pipenv  run  bandit  -r  . Test  results:

>>  Issue:  [Bxxx]

>>  Issue:  [Bxxx]

>>  Issue:  [Bxxx]

The actual output will provide more details.  Not all of these findings are real vulner- abilities, and neither are all findings of bandit real vulnerabilities. Moreover, we limit the scope of our analysis: We only

• focus on software vulnerabilities in the application itself, the Python source code or templates used for generating html pages.  We do not consider configuration issues (for example, using http instead of https or the fact that the application is configured to run in development mode, are out of scope for this exercise).

• classify an issue as a vulnerability, if it can actually be exploited by an attacker.

E6.1. (1 marks):   What is the identifier (e.g., “B105”) and line number/position (e.g, 42:17)

of the first reported vulnerability?  Separate both by a comma (e.g., B105, 42:17). Submit your answer in cell B22 of the spreadsheet.

E6.2. (4 marks):  Can the first reported vulnerability be exploited by an attacker? Submit your answer in cell B23 of the spreadsheet.

E6.3. (1 marks):   What is the identifier (e.g., B105) and line number/position (e.g, 42:17) of the second reported vulnerability? Separate both by a comma (e.g., B105, 42:17). Submit your answer in cell B24 of the spreadsheet.

E6.4. (4 marks):  Can the second reported vulnerability be exploited by an attacker?

Submit your answer in cell B25 of the spreadsheet.

E6.5. (1 marks):   What is the identifier (e.g., B105) and line number/position (e.g, 42:17) of the third reported vulnerability? Separate both by a comma (e.g., B105, 42:17). Submit your answer in cell B26 of the spreadsheet.

E6.6. (4 marks):  Can the third reported vulnerability be exploited by an attacker? Submit your answer in cell B27 of the spreadsheet.