Instructions
User Manual:
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Exercise 4
The application receives two values from the standard input (both terminated by a
newline): (1) mail subject and (2) mail body. For example
./main
Enter the mail subject:
Important message
Enter the mail body:
You won 1000 SEK
The exercise also contains the shell code shell.py. It is generated using make shell,
which produce the binary file shell.bin. If the shell-code is executed, it
invokes exec and execute a cat of /etc/shadow.
Problem 4.1
Forge a subject and e-mail body that make the application to run the shell-code.
Since you probably need to produce input that contains "special" bytes, use the
following procedure:
1. write the python script solution4.py, which prints the forged subject and e-mail
body on the standard output
2. execute ./solution4.py > text to generate a file that contains the forged subject
and e-mail body
3. execute ./main < text
The target attack of the Makefile automates tasks 2 and 3. Your solution consists of
the script solution4.py.
To test your solution execute =./test.py= or =py.test test.py=.
Hints
Debug the program using GDB. Find the distance between the location of the
variable mail_subject and saved eip. Find the memory address of mail_body.
