In Between the Lines
Stage 001
BRIEFING
Difficulty: Introductory
Hey check out this awesome gif I found!
Challenge File: chall.gif
Work/Solution
Opening the image in Preview on my MacBook allows me to step through each GIF frame. on the 7th frame the flag is shown.
flag{sPl1t_53c0nd_v1Ew}
Stage 002
BRIEFING
Difficulty: Medium
I hope you can read fast!
I single-stepped through each frame just like above, and manually transcribed each character.
flag{W31c0M3_70_7H3_111_80X_0F_Ur_UN1M461N4813_P41N_4150_15N7_U51N6_4_0Cr_50_C001_11K3_17_15_U53FU1}
Stage 003
BRIEFING
Difficulty: Hard
What?
The password to the zip file is the flag from In Between the Lines 001.
(flag{sPl1t_53c0nd_v1Ew})
Work/Solution
Unzipped archive to find chall.wav file. Opened .wav in Audacity.
I massaged the spectrogram settings and settled on the following.
Which resulted in the following spectrogram view.
The following is the binary notation of the above spectrogram, with the low frequency being 0 and the high frequency being 1.
0110011001101100011000010110011101111011011011010101010100110101001100010100001101100001011011000101111101100011010010000110000100110001010100100011010101111101
I dropped the above string in cyber chef with the From Binary recipe and got the following decoded string.
flag{mU51Cal_cHa1R5}