5 ms·

I'm on that as well, for me it seems it just decodes some Unicode characters and does arithmetic to print the message, I don't know why it's taking so long or h

by dysoco 7y ago

I'm on that as well, for me it seems it just decodes some Unicode characters and does arithmetic to print the message, I don't know why it's taking so long or how can I speed it up.

koyote 7y ago
It's calculating prime numbers which is why it's slow. Now if only I was to work out which prime numbers it wants... :)
- aereal 7y ago
  have you guys figured it out? I got stuck here too.
  - tbarbour 7y ago
    https://github.com/InverseIntegral/ctf_writeups/tree/master/google_2019/friend_space_book_plus_all_access_red_premium https://github.com/InverseIntegral/ctf_writeups/tree/master/... - great write up of the solution here
  - gctfthroaway 7y ago
    I'm having a hard time even getting it to run. "python vm.py program" results in "SyntaxError: Non-ASCII character '\xf0' in file vm.py on line 19, but no encoding declared;" adding the relevant encoding (# -- coding: utf-8 --) then results in "RuntimeError: Unknown instruction ''\xf0\x9f\x96\x8b\xf0\x9f\x92\xa0\xf0\x9f\x94\xb6\xf0\x9f\x8e\x8c\xf0\x9f\x9a\xa9\xf0\x9f\x8f\x81'' at 370" I assume debugging the program is part of the challenge? Or is it just supposed to work?
    - grafporno 7y ago
      Run it with python3, not 2.7X
- random123456789 7y ago
  Hints: Prime numbers, Palindromes, XOR and offset for later :)
flexer2 7y ago
There's a pretty simple optimization in the labels you can do, but it doesn't really help that much. The first block of letters is XORing with one set of primes that follow a common pattern, but the second one is stumping me. I let it run overnight and basically made no progress once it hit the second block.
danvittegleo 7y ago
Running it with pypy sped it up quite a bit and got it far enough to figure out the remaining portion of the URL.
- ehsankia 7y ago
  Haha, I was gonna try exactly that, but I got too lazy trying to install pypy3 on my shitty centos box. My other option was to translate it into real assembly, but that also seemed like more work that I wanted to put into it.
  - aereal 7y ago
    I guessed the URL, but found nothing on it. I'm guessing the flag may be in the rest of the message to be decoded.
    - dvno42 7y ago
      Check the pngs across the domain. There is something special in at least one of them.
      - aereal 7y ago
        Already checked them out, for EXIF data, visually and also inverted colors. What I am missing? I scrapped and downloaded around 55 pngs.
        ehsankia 7y ago
        Yeah, I found 55 profiles/pngs. Tried ordering the profiles by the image # (from 2 to 56). Noticed the profile names are also a variation of two emojis, so tried looking into binary/morse, but nothing. As the comment above implies, it seems like my approach was wrong and the answer is in one of the images I guess
        aereal 7y ago

by dysoco 7y ago

I'm on that as well, for me it seems it just decodes some Unicode characters and does arithmetic to print the message, I don't know why it's taking so long or how can I speed it up.

koyote 7y ago

It's calculating prime numbers which is why it's slow. Now if only I was to work out which prime numbers it wants... :)

aereal 7y ago
have you guys figured it out? I got stuck here too.
- tbarbour 7y ago
  https://github.com/InverseIntegral/ctf_writeups/tree/master/google_2019/friend_space_book_plus_all_access_red_premium https://github.com/InverseIntegral/ctf_writeups/tree/master/... - great write up of the solution here
- gctfthroaway 7y ago
  I'm having a hard time even getting it to run. "python vm.py program" results in "SyntaxError: Non-ASCII character '\xf0' in file vm.py on line 19, but no encoding declared;" adding the relevant encoding (# -- coding: utf-8 --) then results in "RuntimeError: Unknown instruction ''\xf0\x9f\x96\x8b\xf0\x9f\x92\xa0\xf0\x9f\x94\xb6\xf0\x9f\x8e\x8c\xf0\x9f\x9a\xa9\xf0\x9f\x8f\x81'' at 370" I assume debugging the program is part of the challenge? Or is it just supposed to work?
  - grafporno 7y ago
    Run it with python3, not 2.7X
random123456789 7y ago
Hints: Prime numbers, Palindromes, XOR and offset for later :)

flexer2 7y ago

There's a pretty simple optimization in the labels you can do, but it doesn't really help that much. The first block of letters is XORing with one set of primes that follow a common pattern, but the second one is stumping me. I let it run overnight and basically made no progress once it hit the second block.

danvittegleo 7y ago

Running it with pypy sped it up quite a bit and got it far enough to figure out the remaining portion of the URL.

ehsankia 7y ago
Haha, I was gonna try exactly that, but I got too lazy trying to install pypy3 on my shitty centos box. My other option was to translate it into real assembly, but that also seemed like more work that I wanted to put into it.
- aereal 7y ago
  I guessed the URL, but found nothing on it. I'm guessing the flag may be in the rest of the message to be decoded.
  - dvno42 7y ago
    Check the pngs across the domain. There is something special in at least one of them.
    - aereal 7y ago
      Already checked them out, for EXIF data, visually and also inverted colors. What I am missing? I scrapped and downloaded around 55 pngs.
      - ehsankia 7y ago
        Yeah, I found 55 profiles/pngs. Tried ordering the profiles by the image # (from 2 to 56). Noticed the profile names are also a variation of two emojis, so tried looking into binary/morse, but nothing. As the comment above implies, it seems like my approach was wrong and the answer is in one of the images I guess
        aereal 7y ago