Challenge 34: 1_wanna_b3_a_r0ck5tar

Description

I wrote you another song. Put the flag in the picoCTF{} flag format

Tags

picoCTF 2019 General Skills

Points

350

Solution

This challenge is a follow up of mus1c challenge. In this challenge, we are given a file named lyrics.txt. we can use cat to read the file.

If we try to run the code in the online interpreter, we will get the following error:

Rock is electric heaven
       ^
Expected [A-ZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞĀĂĄĆĈĊČĎĐĒĔĖĘĚĜĞĠĢĤĦĨĪĬĮİIJĴĶĸĹĻĽĿŁŃŅŇŊŌŎŐŒŔŖŘŚŜŞŠŢŤŦŨŪŬŮŰŲŴŶŸŹŻŽ] or [a-zàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþāăąćĉċčďđēĕėęěĝğġģĥħĩīĭįıijĵķĸĺļľŀłńņňŋōŏőœŕŗřśŝşšţťŧũūŭůűųŵŷÿźżžʼnß] but " " found.
line 21 col 8

So we Cannot run the code in the online interpreter. But if we do a little bit of research, we will find that the Rockstar programming language has compilers for many languages. We can use the Rockstar compiler to compile the code to python.

After installing the compiler, we can run the following command to compile the code:

rockstar-py -i lyrics.txt -o lyrics.py

We will get the following python code:

Rocknroll = True
Silence = False
a_guitar = 10
Tommy = 44
Music = 170
the_music = input()
if the_music == a_guitar:
    print("Keep on rocking!")
    the_rhythm = input()
    if the_rhythm - Music == False:
        Tommy = 66
        print(Tommy!)
        Music = 79
        Jamming = 78
        print(Music!)
        print(Jamming!)
        Tommy = 74
        print(Tommy!)
        They are dazzled audiences
        print(it!)
        Rock = 86
        print(it!)
        Tommy = 73
        print(it!)
        break
        print("Bring on the rock!")
        Else print("That ain't it, Chief")
        break

We Can See the code is not valid python code. and we cannot run it, if we try to under stand it we will find that it is a simple code that will print some numbers but if we noticed the code we will find a comment that says They are dazzled audiences If we know try to run the following code, in the online interpreter

They are dazzled audiences
shout They

we will get this output:

79

So we can see that the code is trying to print the ASCII value of the string They are dazzled audiences.

So we got all the numbers that the code is trying to print. So we can use the following python code to get the flag:

>>> ''.join([chr(int(i)) for i in '66 79 78 74 79 86 73'.split()])
'BONJOVI'

So lets put the flag in the picoCTF{} flag format

Flag

picoCTF{BONJOVI}