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Google CTF 2019

capturetheflag.withgoogle.com

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Re: Google CTF 2019

#101

Post by tambourine_man »

saagarjha wrote: post #86
tambourine_man wrote: post #69

Earlier quoted context omitted.

Companies are not countries. People are hired in the first and born in the second. Companies should be concerned when their actions don't match the narrative they are trying to sell about themselves. If the Mobile Web is important to Google (and it should be), it must be a company wide effort. The “that's not my department” excuse doesn't cut it.

"I'm always amazed at how a college that has the most number of Nobel prize winners has some professors that can't do calculus"

That's a better analogy.

Still, colleges are usually much more eclectic than companies. Even MIT, usually known for STEM, has one kick ass humanities department.

Re: Google CTF 2019

#102

Post by tambourine_man »

q3k wrote: post #94
tambourine_man wrote: post #52

I’m always amazed how a company that creates the world’s most popular mobile OS and web browser is unable to code a decent mobile webpage. Scrolling this page is sufferable, anchor links don’t work well, etc. Basic stuff. Look no further than G Suite, Google Cloud for more examples.

The entire competition is a volunteer/20% thing internally. It doesn't go through the same design cycle as official Google products. For this year, they also rewrote the scoreboard site for scratch (it's now uses Firebase). [source: I was the on-call SRE for the 2017 edition]

I believe you, still, it's hosted at a Google's domain and it's a company's core competency. I don't think that's excusable.

Re: Google CTF 2019

#104

Post by flexer2 »

dysoco wrote: post #70
Tepix wrote: post #43

The emoji virtual machine (step 3 or 4) is cool. I'm trying to understand what it does to speed it up.

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.

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.

Re: Google CTF 2019

#106

Post by gabmiral »

tambourine_man wrote: post #52

I’m always amazed how a company that creates the world’s most popular mobile OS and web browser is unable to code a decent mobile webpage. Scrolling this page is sufferable, anchor links don’t work well, etc. Basic stuff. Look no further than G Suite, Google Cloud for more examples.

I mean, it's not like this CTF requires you to unzip data, use a terminal (decrypt Base64, use Telnet and python scripts) and read weird files with unreadable characters

Re: Google CTF 2019

#107

Post by danvittegleo »

dysoco wrote: post #70
Tepix wrote: post #43

The emoji virtual machine (step 3 or 4) is cool. I'm trying to understand what it does to speed it up.

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.

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

Re: Google CTF 2019

#108

Post by ehsankia »

chris92de wrote: post #100
tito3 wrote: post #59

Earlier quoted context omitted.

Stuck on this one, can see readme.flag but not sure how to proceed

i ended up using fold. theres also has to be a way to read the ORME.flag by modifying the file permissions but i haven't figured that one out yet.

Yeah I went through all of the non-deleted commands and fold ended up being the one I found too. The beginning instruction says some levels have multiple flags, so I'm guessing ORME.flag is the hardmode flag.

Re: Google CTF 2019

#109

Post by ehsankia »

danvittegleo wrote: post #107
dysoco wrote: post #70

Earlier quoted context omitted.

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.

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

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.

Re: Google CTF 2019

#110

Post by ehsankia »

dexhunter wrote: post #103

stuck on https://govagriculture.web.ctfcompetition.com/ this task, any help?

Same here. Unless there's some steganography, I'm really all out of ideas. I see see the content of folders (/static/, /static/images/, etc), but that doesn't help. I can't get anything out of /admin and the content of /post don't appear anywhere for any sort of XSS attack.
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