QR Code

We are given an image containing a QR code:

If we scan it, we will get this string:

c3ludCB2ZiA6IGEwX29icWxfczBldHJnX2RlX3BicXI=  

It seems to be encoded in Base64, let’s try to decode it:

$ echo c3ludCB2ZiA6IGEwX29icWxfczBldHJnX2RlX3BicXI= | base64 -d  
synt vf : a0_obql_s0etrg_de_pbqr

But we don’t see anything readable. There seems to be a substitution algorithm such as ROT13. Let’s go to CyberChef and check it out:

We see: “flag is : n0_body_f0rget_qr_code”, so the flag is: CTFlearn{n0_body_f0rget_qr_code}.