Rating:
In the question we are provided with a file with “Extension Error” after checking its
header file, It was really clear it is a GIF file.
Converting this file to GIF will show result like this,
After checking some data related to this GIF like strings, frames, and steghide I checked
its metadata and got a string in comments which was in base64 format.
dmlzaHdhQ1RGe3ByMDczYzdfdXJfM1gxRn0=
Decrypting this to plain text got me to the Flag.
```FLAG: vishwaCTF{pr073c7_ur_3X1F}```