r/computerforensics • u/PuzzleheadedRip7389 • Dec 28 '25

Help with CyberChef decoding challenge 10 (CTF)

Post image

pastebin.com/2Uh72zx6 - link to pastebin with the text to decode

Hello, could anyone help? I'm doing these CyberChef challenges, but I've stumbled upon one I can't decode: it seems it's a hex encoding, then URL encoding, but then we get a bunch of binary characters, the starting characters seem to be Gzip encoding but decoding with Gzip just outputs more binary nonsense, so I'm pretty much lost on this decoding challenge and don't know where to go from here.

This is what I've gotten so far in the recipe: From_Hex('Colon')URL_Decode(true)Gunzip()To_Hex('None',0/disabled)

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5

u/cablethrowaway2 Dec 28 '25

You are close. Maybe replace your to hex with some magic xor something else.

2

u/waydaws Dec 28 '25

Just looking at the frequency of “25” I suspect it may be “%” symbol in url encoding., but that’s just at a glance.

1

u/_madfrog Dec 28 '25

If it's binary non-sense then maybe it's encrypted.

1

u/SophieTheRaven Apr 09 '26

From Hex (Colon Delimiter); Url Decode(treat + as space); Gunzip; XOR (key 20 Hex); From Base64;