first i inspected the jpeg,it looked normal, so I started with output.bin. Its size was 2112 bytes, which is 264 * 8. Splitting it into 8-byte chunks showed a simple pattern: every chunk was either all ff, or some random-looking bytes.
So I took each 8-byte chunk as one bit
like
ff ff ff ff ff ff ff ff = 0others = 1when i pack those MSB i got
\xa0d3f1n173ly_n07_4_53cR37_p4$$w0Rd
so i found the textt
d3f1n173ly_n07_4_53cR37_p4$$w0Rd
used this as a steghide password for the jpeg image and i got the flag
Flag : RMCTF{m37h0d_b3h1nd_7h3_m4dn355!}
On hearing the sound itself i found that it is a sstv signal so used an online decoder to solve this.
https://sstv-decoder.mathieurenaud.fr/
