Image Strings | Ryan's CTF [07] "Stenography"

Key Takeaways

this challenge from Ryan Nicholson CTF is called stenography I'm assuming this is supposed to be steganography whatever that's okay we'll let it pass it says find the hidden flag in this attached image file so we can go ahead and download this I will W get it into our location in the command line did not copy fail I was probably just hitting the N button whatever so we can do G this hacker file and view it if we particularly wanted to it is just some dude staring at a computer screen so maybe there's some interesting stuff hidden in different colors in this so we can use some of our own regular steganography techniques particularly take a look at this file z stag we can pass to it however it is a JPEG file which Z SEC does not have support for so what I like to do is actually run stag solve on it which is a jar file you can find online if you particularly want to use this tool it's pretty awesome in a really good go to like low-hanging fruit technique for actually viewing anything that may be steganography you can go through it and actually look at different planes or however specific bit in a specific color like green pane or blue plane the zero bit like mode ever maybe if you get a loo significant bit or actually if you it an X or inverted colors and any Alpha characters etc so that's a good tool for some challenges however it's not doing the doing for us in this one so what I actually tried at some point was just running strings on this file and I noted at the very very bottom there is a base64 line you can tell us base 64 because of the random capitalizations and numbers also the two equal signs give it away and agree just matter because equal signs at the very end tell us it's basics t4 for padding we can pass this to base64 tack D and we simply get the flag just like that there are a couple extra spaces in this so I will Rev this to actually cut out the delimiter and get the first one and then rev it back and then we have our flag so we can take this code or this command it take note of that as our get flag script and include our shebang line and we have a documented solution great so now we can mark that challenge as complete and we can submit that for points and move on so good thing to note when you're doing second ography I don't really consider this diagraph II because maybe this is forensics there's a string embedded or hidden in the file it's not in the actual color or pixels or images in the picture itself but still cool challenge good to submit that and learn about it so hey I want to give the special shout-out to my supporters people who loved me on patreon thank you I love you I was gonna start singing Barney for a second there that was weird hey $1 a month on patreon will give you a special shout-out just like this at the end of every video $5 a month on patreon will give you early access everything they're released on YouTube and I'll hopefully get more incentive soon if you did like this video please do press that like button maybe comment maybe subscribe and if you're willing to come check us out on discord hang out with us in there and support me on patreon that'd be super cool links in description see ya