AC31012/AC51042 Information Security -Solved

As a starting point for developing your login procedure, you can read the following Stack Overflow 
post: 
• Generate sha256 with OpenSSL and C++ 
Functionality of the Login Procedures 
Your secure and subverted login procedures must both satisfy the following requirements: 
• R1: The login procedure must work with the password file format described in the previous 
section. 
• R2: It must include the authlib.h header file and use the two functions defined therein. 
• R3: It must call the function void authenticated(std::string u), where u is the username, 
whenever a user enters a correct username and password pair. 
In addition, your secure login procedure must satisfy the following requirements: 
• R4: It must call the function rejected(std::string u) if an invalid username and password pair 
was entered. 
• R5: It must not call authenticated(std::string u) unless a correct username and password 
pair for username u was entered. 
It is up to you to decide whether your secure and subverted login procedures offer the user one or 
more attempts to log in before rejecting and exiting. Your secure and subverted login procedures 
may offer additional functionalities, which may help disguise backdoors, but shorter backdoored 
login submission will receive more marks (see the marking scheme for details on this). 
You must not modify authlib.h or authlib.cpp. You cannot assume that the 
functions in authlib.cpp will be implemented in the same manner when your code is 
tested, so do not rely on this as part of the design of your login procedures. Likewise, you 
can modify the passwords file as you work on your login procedures, but you cannot 
change the filename or assume anything about the contents of this file when your code is 
tested, other than they will follow the format above.Submission 
This assignment must be handed in by one student in each group. Submit your assignment as a 
single ZIP file named after your group by the deadline. 
The ZIP file must contain: 
1) A file login.cpp. This is the secure password login procedure. Your login.cpp program must: 
a) satisfy requirements R1–R5 above, 
b) compile without warnings when the flags -Wall -pedantic -Wextra are used, 
c) hash the submitted passwords with openssl’s sha256 hash function, 
d) contain fully commented source code. 
2) A file login-subverted.cpp. This is the password login procedure with a backdoor. Your 
backdoor must: 
a) allow you to login as root or any other user on the system without knowing their 
passwords, 
b) satisfy requirements R1–R3 above, 
c) compile without warnings when the flags -Wall -pedantic -Wextra are used, 
d) hash the submitted passwords with openssl’s sha256 hash function, 
e) contain fully commented source code (but comments may be misleading ;). 
3) A file report.pdf. This PDF file documents the vulnerability in your backdoored login procedure. 
Your report must : 
a) be no more than 1 page and list the team name and team members, 
b) describe the steps to trigger the vulnerability, i.e. how can an attacker login without 
knowing a user’s password, 
c) show where the vulnerabilities are in the code, 
d) explain why you think that your vulnerabilities are difficult to detect, 
4) A Makefile. This file compiles both your secure and your subverted login procedures.Marking Scheme 
A grade 
B grade 
C grade 
D grade 
Fail 
Mark 
The login.cpp source 
code is secure, 
correct, works with 
hashed password 
database and is 
thoroughly 
commented. 
10 to 7 marks 
The login 
procedure works 
correctly, i.e., 
satisfies 1a, 1b, and 
1c. 
6 marks 
login.cpp compiles 
but only satisfies two 
of the three 
conditions 1a, 1b, 1c. 
5 marks 
login.cpp compiles 
but only satisfies 
one of the three 
conditions 1a, 1b, 
1c. 
4 marks 
login.cpp 
not submitted, 
or it does not 
compile or does 
not satisfy any of 
the conditions 1a, 
1b, 1c above. 
3 to 0 marks 
Comments: 
The login
subverted.cpp source 
code is works with 
hashed password 
database and is 
thoroughly 
commented. 
(Comments are 
allowed to be 
misleading!) 
10 to 7 marks 
The login
subverted 
procedure works 
correctly with the 
hashed password 
database and does 
not produce 
compiler warnings 
(i.e. satisfies 2a, 2b, 
2c, and 2d.) 
6 marks 
The login-subverted 
procedure compiles 
but only satisfies two 
of the three 
conditions 2a, 2b, 2c, 
2d. 
5 marks 
Login-subverted.cpp 
compiles but only 
satisfies one of the 
three conditions 2a, 
2b, 2c, 2d. 
4 marks 
Login
subverted.cpp 
not submitted, 
or it does not 
compile or does 
not allow the 
attacker to 
authenticate as 
another user. 
3 to 0 marks 
Comments: 
The vulnerability is 
well explained its 
covertness is well
justified. It is clear 
that research has 
been taken into this 
area and alternatives 
considered. 
10 to 7 marks 
All three sections 
are adequately 
described. 
6 marks 
1 out of the three 
mandatory sections 
(see 3a, 3b, 3c, 3d 
above) is 
inadequately 
covered. 
5 marks 
2 out of the 3 
mandatory sections 
(see 3a, 3b, 3c, 3d 
above) are 
inadequately 
covered. 
4 marks 
Inadequate report 
or no report.pdf 
submitted. 
3 to 0 marks 
Comments: 
All files (Makefiles, 
report, cpp sources) 
are submitted in the 
required file format 
and structure. The 
report is not longer 
than 1 page. 
10 to 7 marks 
Minor issues in one 
of the submitted 
files or with the 
submission (e.g., 
naming, missing 
team members, 
etc.). 
6 marks 
One or more files 
inadequately 
submitted or minor 
issues with two or 
more files. 
5 marks 
One file missing. 
4 marks 
Two or more files 
missing. 
3 to 0 marks 
Comments: 
Marks awarded by 
ranking submissions 
from shortest to 
longest in number of 
“;” and “,” used in 
source code. 
10 to 7 marks 
Code is obfuscated 
as, e.g., HEX strings 
in order to 
minimize number 
of “;” and “,”. 
6 marks 
Sum of “;” and “,” 
characters in source 
code of subverted 
login is greater than 
65. 
5 marks 
Sum of “;” and “,” 
characters in source 
code of subverted 
login is greater than 
100. 
4 marks 
Inadequate 
subverted login 
procedure 
submitted (e.g., 
implemented w/o 
hash function.) 
3 to 0 marks 
Comments: