## Beginner/Headache (351 solves)Created by: `Sl4y3r_07`> I've had a headache since last evening. Is there a magic spell that can cure it immediately?
At an original look at this challenge I got stumped for a while overlooking something very minor...
We start with a seemingly 'corrupt' file, `chal.png` which doesn't open. I check EXIF first:
```$ exiftool chal.pngExifTool Version Number         : 12.70File Name                       : chal.pngDirectory                       : .File Size                       : 90 kBFile Modification Date/Time     : 2023:12:18 14:43:09+11:00File Access Date/Time           : 2023:12:18 18:10:35+11:00File Inode Change Date/Time     : 2023:12:18 18:10:33+11:00File Permissions                : -rw-rw-r--File Type                       : PNGFile Type Extension             : pngMIME Type                       : image/pngImage Width                     : 1265Image Height                    : 687Bit Depth                       : 8Color Type                      : RGB with AlphaCompression                     : Deflate/InflateFilter                          : AdaptiveInterlace                       : NoninterlacedImage Size                      : 1265x687Megapixels                      : 0.869```Nothing... Anything trying binwalk?```$ binwalk -e chal.pngDECIMAL       HEXADECIMAL     DESCRIPTION--------------------------------------------------------------------------------41            0x29            Zlib compressed data, compressed```Nothing of interest in the data... So here I get stumped until I decide to check the bytes...
Files have 'signatures' (magic numbers). PNGs magic numbers are `89 50 4e 47 0d 0a 1a 0a`. This does not match our files magic numbers (`ae 71 00 ff 3d 62 24 6d`)
So... I change the files magic bytes to be the correct bytes, and we get the following image (that opens!).
![Image after fixing magic bytes](https://seall.dev/images/ctfs/backdoorctf2023/headache.png)
There's our flag! `flag{sp3ll_15_89_50_4E_47}`
**Files:** [public.zip](https://web.archive.org/web/20231218155709/https://backdoor.infoseciitr.in/uploads?key=8823502df1ed5ebf77a70f66f2cb4d3551cc167477a7cc7d5525a04ef7559255%2Fpublic.zip)