Sunshine CTF rev middle-endian
Sunshine CTF 2022
Here at Chompy Game Studios, we have developed a brand-new byte ordering scheme: middle endian! This transformative scheme will surely impress our shareholders! Can you reveal the secret contained within?
(Special thanks to Oreomeister for the concept)
We are given a hex file that has the name flag.png.me
.
The file appears to be scrambled, as the name implies:
After looking at the name of the file we can imply that the png header and footer should be present.
So we should see something like this at the end:
And something like this in the beginning:
By searching at the end of our input scrambled file we can see we can form a png header by mixing the top and end most parts of the file.
End part of the input file:
Afterwards we make a python script for demangling:
for i in range(int(len(a)/2)):
temp=a[i*2+1]
a[i*2+1]=a[-i*2-1]
if i*2>len(a)/2 or -i*2-1<-len(a)/2:
break
a[-i*2-1]=temp
And we get the image:
and
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