Decyphering something like these was a part of so many job interviews
I'm mystified why an interviewer would want to know "has this guy memorized that adding two empty arrays in javascript nets 'empty string'?"
JSFuck (2012)
51–60 of 168 posts
Re: JSFuck (2012)
#52I probably deserve to get downvoted to oblivion for this but... I've deployed JSFuck in production! We wanted to obfuscate this bit of code, to make life just a little bit harder for reverse engineers. We made this huge function where we pretty much passed in all our application state, and it would run this JSFuck code, and spit out a token. We even made a few tweaks to the code so that you couldn't just reverse it b…
For someone to reverse your code, all they need to do is run it through this.
https://enkhee-osiris.github.io/Decoder-JSFuck/Re: JSFuck (2012)
#53New interview question: What will be the result of running the following code? [][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[ ]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]][([][(![]+[])[+[]]+([![]]+[][[] ])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+ (!![]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+([![]]+[][[]])[+ !+[]+[+[]]]+(![]+[])[!+[]+!+[…
I think someone once asked me the simplified variant of that question. What is the result of: []+[] And I didn’t know the answer to that (I mean, who does that kind of fuckery in Javascript, you can’t sum arrays). I would have no chance with these Google level questions.
The right type of answer for that is to laugh and say, "you should ask the fool who wrote that code instead of asking me."
Re: JSFuck (2012)
#54This is honestly quite disappointing compared to prior art. https://metacpan.org/pod/Acme::EyeDrops
Re: JSFuck (2012)
#55Hmm, this could actually be useful: [][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]][([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+…
I bet you feel Rick Rolled. I have NoScript! I'm glad you didn't write something like
location="http://y2u.be/dQw4w9WgXcQRe: JSFuck (2012)
#56I don't understand how this works. I've seen brainfuck before, but not truly understood it. How is it possible to open up a new tab, paste the encoded form, and have working JavaScript?
brainfuck isn't an obfuscator, but a language with a very small and simple instruction set. Technically it falls somewhere between c and assembly, since it doesn't have a 1:1 relationship with machine code, but in practice it is less powerful than assembly because you have to work within the confines of its restrictive conventions to recreate something as simple as y = x
There are some tasks which lend themselves to the way the language is constructed, and can be done with few instructions.
Reversing a string, for example, is just ,[[>[>],]And a destructive y = y + x is just [->+<] (destructive because this also sets x to zero)
Re: JSFuck (2012)
#57New interview question: What will be the result of running the following code? [][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[ ]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]][([][(![]+[])[+[]]+([![]]+[][[] ])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+ (!![]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+([![]]+[][[]])[+ !+[]+[+[]]]+(![]+[])[!+[]+!+[…
I think someone once asked me the simplified variant of that question. What is the result of: []+[] And I didn’t know the answer to that (I mean, who does that kind of fuckery in Javascript, you can’t sum arrays). I would have no chance with these Google level questions.
looks like you need to watch the WAT talk
Re: JSFuck (2012)
#58I probably deserve to get downvoted to oblivion for this but... I've deployed JSFuck in production! We wanted to obfuscate this bit of code, to make life just a little bit harder for reverse engineers. We made this huge function where we pretty much passed in all our application state, and it would run this JSFuck code, and spit out a token. We even made a few tweaks to the code so that you couldn't just reverse it b…
makes me sad to hear that :( I will say, as a reverse engineer, that javascript minifiers like closure compiler will optimize almost all obfuscation out, and the rest you can usually translate to a form which it can understand and then it will do the rest. The effect of obfuscation is not what you expect. It seems like it moves the whole difficulty up, but it only moves up the floor. By doing so it tends to remove al…
I'm curious: can you can undo the obfuscation of JScrambler and Obfuscator.io easily? Some time ago I tried to run both through Closure Compiler, but it was way harder than I thought would be.
Re: JSFuck (2012)
#59I probably deserve to get downvoted to oblivion for this but... I've deployed JSFuck in production! We wanted to obfuscate this bit of code, to make life just a little bit harder for reverse engineers. We made this huge function where we pretty much passed in all our application state, and it would run this JSFuck code, and spit out a token. We even made a few tweaks to the code so that you couldn't just reverse it b…
For someone to reverse your code, all they need to do is run it through this. https://enkhee-osiris.github.io/Decoder-JSFuck/
I think you missed this sentence from the comment you're replying to:
> We even made a few tweaks to the code so that you couldn't just reverse it back into JS with something like https://enkhee-osiris.github.io/Decoder-JSFuck/.
Re: JSFuck (2012)
#60I actually had a chance to meet Martin once during JSConf in Singapore back in November 2014. Very cool guy with a hysterically fucked up humor with JS.
I mean... http://aem1k.com/world speaks for itself.
JSFuck was included in his presentation back then and boy did it inspire me to do more JS. Here we are, a little under 7 years later, still in the JS world.