Ghost Wrangler
Running ./ghost gives us the following output:
./ghost
| _| I've managed to trap the flag ghost in this box, but it's turned invisible!
Can you figure out how to reveal them?
The characters between the pipes are just 0x20, so there's nothing of interest there.
Running strings ghost gives us a lot of output, but the most interesting part is the following, which is right above the string from the prompt:
u/UH
[]A\A]A^A_
[GQh{'f}g wLqjLg{ Lt{#`g&L#uLpgu&Lc'&g2n%s
[4m%*.c
[24m|
Running magic on CyberChef with a depth of 5, intensive mode, and extensive language support showed us that the following operation returned the flag:
XOR({'option':'Hex','string':'13'},'Standard',false)
HTB{h4unt3d_by_th3_gh0st5_0f_ctf5_p45t!}