• Saturday , 6 June 2020

Solving a JavaScript crackme: JS SAFE 2.0 (web) – Google CTF 2018

Code Canyon



Solving a crackme implemented in JavaScript that attempts to obfuscate the algorithm through some anti-debugging.

Solution Script / HTML: https://gist.github.com/LiveOverflow/bbdffe3777ce0f008b452e0a789cef65
John Hammond: https://www.youtube.com/user/RootOfTheNull

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#CTF

Original source

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42 Comments

  1. Aditya Vallabh
    May 1, 2019 at 17:25

    The confusion with the x's isn't cuz of the with statement. The parameter х (U+0445 or 1093) isn't the x from the English alphabet. It is a Cyrillic alphabet which only looks like it. And this input variable was never used in the code except for the last eval() which dynamically generated 'х==c(weird_string,h(х))' referring to our input х. THAT was the beauty of the challenge 😛

  2. dr?w
    May 1, 2019 at 17:25

    You put foo variable which is a string in a str function, it's like transforming a string in a string

  3. Fierce Thunder
    May 1, 2019 at 17:25

    I'm an outsider looking in. I tried to figure it out, but as far as I can tell "x" provides the password in hidden and obscured fashion. That of course being the main difficulty. Me having little knowledge of JS I know I would be incapable of solving for "x" assuming my assessment here is correct.

  4. 1024
    May 1, 2019 at 17:25

    The with statement makes it hard for the interpreter to understand how to interpret it (or something) lmao

  5. Dave Google
    May 1, 2019 at 17:25

    Google CTF and you run google chrome hahahah 😛

  6. Hakim Norizman
    May 1, 2019 at 17:25

    How do you open the source code for the html

  7. Thulahdanlauss
    May 1, 2019 at 17:25

    Love you videos, i'm gradually learning more and more thanks to you ! Your explainations helps me understand the mindset behind these CTF, hopefully with more knowledge and time i'll be able to clear some CTF one day 🙂 Cheers !

  8. Ilshidur
    May 1, 2019 at 17:25

    Uuuuuh. I guess some people used the solution in this video to validate the challenge … To people doing this : you are stupid to cheat on a challenge.

  9. fried programmer
    May 1, 2019 at 17:25

    they updated it and it's still a nightmare

  10. Mario Guglia
    May 1, 2019 at 17:25

    12:49 basically nobody in the world knows what it does 🤣🤣🤣

  11. Gwenny Cake
    May 1, 2019 at 17:25

    I didn't understand a shit, but I loved it! I subscribed!

  12. manta
    May 1, 2019 at 17:25

    I'm a long-time computer enthusiast with 'okay' coding skills (intermediate skill perhaps?) and I'm starting my compsci course at uni this year. Thanks for the cool videos. I hope I can practice and get to the point where my style of thinking makes these kinds of problems a matter of 'intuition' like it seems to be for you and definitely others who do CTFs.

  13. one hour music
    May 1, 2019 at 17:25

    When I actually dont understand a single word…

  14. Itskos Leonidas
    May 1, 2019 at 17:25

    wait WHAT?!

  15. peng peng
    May 1, 2019 at 17:25

    crazy man ~~!!!

  16. Kenny Cheung
    May 1, 2019 at 17:25

    You sir said you were a noob at this, then I should be an insect lol

  17. Steve01ification
    May 1, 2019 at 17:25

    Both noobs lol!

  18. Lorenz Nickel
    May 1, 2019 at 17:25

    funny

  19. Edward Brownstien
    May 1, 2019 at 17:25

    Seems the more I learn, the more I realize I don't know. ( -_-)

  20. ubiquity
    May 1, 2019 at 17:25

    This is why I don't trust JavaScript programmers. Shit like this is what nightmares are made of.

    In Typescript we trust. All day er' day

  21. blueRhino
    May 1, 2019 at 17:25

    Great video!
    Are there any similiar websites where you can practice JS by solving similiar tasks (I still feel I’m not ready to join CTF) ?
    Any recommendations are welcome.

  22. Code Chapter
    May 1, 2019 at 17:25

    I love you videos and im kinda binge watching them

    keep up the good work!

  23. oldbootz
    May 1, 2019 at 17:25

    If you have a look at the file for this challenge now its quite different!

  24. multimateco
    May 1, 2019 at 17:25

    !SpamAndHex❤️❤️❤️

  25. BubyM B
    May 1, 2019 at 17:25

    These naming conventions hurt my head

  26. Phoelee
    May 1, 2019 at 17:25

    Man… my mind is blown… holy smokes…

  27. Vagabond
    May 1, 2019 at 17:25

    cucked by x

  28. XLBZ
    May 1, 2019 at 17:25

    whenever i feel like im getting the hang of coding i just watch one of these videos so i realize i know nothing again

  29. metal wellington
    May 1, 2019 at 17:25

    Jesus Christ and that was an easy one…

  30. SeriousGamer753
    May 1, 2019 at 17:25

    If this is considered really easy i think i shouldnt even think of pursuing coding

  31. Christian Kaindl
    May 1, 2019 at 17:25

    This is so crazy cool 😱

  32. Sp1nZer
    May 1, 2019 at 17:25

    i srsly dont understand shit about this but its really cool man keep up the good work

  33. Oh living TACOS
    May 1, 2019 at 17:25

    BRAYN TOO PEENOOT SISD TÜ UNDRSTUND

  34. TechnoMulen
    May 1, 2019 at 17:25

    this gave me long hair. I understood 0.000%

  35. Dominik M
    May 1, 2019 at 17:25

    was mache ich hier eigentlich

  36. Joseph Michael Añover
    May 1, 2019 at 17:25

    14:03 made me just say "Uhhhhhhhhhhhhhhhhhhhhhhhhhhhhh…yeah?" 🙁 I'm a fuckin' idiot

  37. ZX Spectrum
    May 1, 2019 at 17:25

    this is like mathmatical composition on xanax

  38. AinP
    May 1, 2019 at 17:25

    Is Ctf challenges good practise for noobs like me? It seems fun

  39. Peaky_Blinder
    May 1, 2019 at 17:25

    Where can I learn all this stuff
    Where do you start ?

  40. Ginger TheNinjer
    May 1, 2019 at 17:25

    What just happened…

  41. Lokendra Sharma
    May 1, 2019 at 17:25

    Thanks. It was informative. Will check John Hammond's channel as well. Really like that how much great online content is produced nowadays 🙂

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