https://meashiri.github.io/ctf-writeups/posts/202312-backdoorctf/#forenscript
TLDR:  Two layers to this problem. 1. The given binary data is a PNG file with every 4 bytes flipped in order. 2. Once the order is corrected, we can see that there is a second PNG file attached to the end of the first red herring PNG. Extract the second image to get the flag. 
```bash% xxd -c4 -p a.bin | sed -E 's/(..)(..)(..)(..)/\4\3\2\1/g' | tr -d '\n' | xxd -r -p | dd skip=60048 of=b.png ibs=1# open b.png and get the flag```