... can read this instantly
I found this obfuscated code on a public FTP-Server. But I don't understand what it's doing...
After analyzing given file it looks like two lines of an obfuscated Python code. When you try to run it as is you get SyntaxError: invalid syntax.
Let's take a closer look at the first line of code. It calls exec and passes some obfuscated text as its argument. The first thing which comes to my mind is to change exec to print, comment out the second line and run the program to see what is going on inside.
$ python True.1337
A=chr;__1337=exec;SANTA=input;FUN=print
def _1337(B):return A(B//1337)The first line of output defines aliases and the second one defines a function _1337. When we apply given alias for A we get this line of code.
def _1337(B):return chr(B//1337)Now it's time to analyze the second line. We know that __1337 is alias for exec. Let's try the same thing as we did with the first line and print the result.
C=SANTA("?")
if C=="1787569":FUN(''.join(chr(ord(a) ^ ord(b)) for a,b in zip("\x7B\x67\x05\x06\x18\x4D\x5A\x07\x46\x1E\x5F\x4D\x0C\x43\x14\x5F\x03\x58\x0B\x19\x5C\x07\x45\x52\x1E\x46\x5B\x58\x13","31415926535897932384626433832")))When we apply the rest of aliases and remove the input check we get this simple Python code.
print(''.join(chr(ord(a) ^ ord(b)) for a,b in zip("\x7B\x67\x05\x06\x18\x4D\x5A\x07\x46\x1E\x5F\x4D\x0C\x43\x14\x5F\x03\x58\x0B\x19\x5C\x07\x45\x52\x1E\x46\x5B\x58\x13","31415926535897932384626433832")))The last step is to run this code and the flag gets printed.
HV17-th1s-ju5t-l1k3-j5sf-uck!