https://osiriz.dev/tags/steganography/Recent content in steganography on OsirizHugo -- gohugo.ioen-usWed, 14 Dec 2022 10:30:00 +0100https://osiriz.dev/posts/2022/12/nc3ctf-2022-stego/Wed, 14 Dec 2022 10:30:00 +0100https://osiriz.dev/posts/2022/12/nc3ctf-2022-stego/10 We get a file called et-nul, running file tells us it is a long line of ASCII characters: $ file et-nul et-nul: ASCII text, with very long lines (1330), with no line terminators The file contains: 0110000110011111100011111110000111101111111101111111100000000011000011011000001101100000000000000011111111011110110000000000000001100001101111001111110001111110011111111011000011011110111100011100011011000011011000001100110000110000000000110000000000001110001101100000110110000000000000000001100000110011000000000000000111000110011001100001101100001101100000001110001101111000011001111001101100000000000000110011000011000000000011000000000000111100110110000011011000000000000000000110000011001100000000000000011110011001100110000000110000000110000000111100110111100001100110110110110000000011111110011100001111110000001100000000000011011011011000001101100000000000000000011000001100110000000000000001101101100110001111110001111110011111100011011011001100000111011001111011000000000000001100110000110000000000110000000000001100111101100000110110000000000000000001100000110011000000000000000110011110011000000001100000001101100000001100111100000000011001100011101100001101100000110011000011000000000011000000000000110001110110000011011000000000000000000110000011001100000000000000011000111001100110000110110000110110000000110001110111100001100110000110011111100011111110000111101111111100001100001111111011000011001111111001111111101111111000011000011110111111110111111101100001101111001111110001111110011111111011000011011110111100 By splitting the text into 7 lines of equal length the message reveals itself (don’t focus too hard or you wont see it): 0110000110011111100011111110000111101111111101111111100000000011000011011000001101100000000000000011111111011110110000000000000001100001101111001111110001111110011111111011000011011110111100 0111000110110000110110000011001100001100000000001100000000000011100011011000001101100000000000000000011000001100110000000000000001110001100110011000011011000011011000000011100011011110000110 0111100110110000000000000011001100001100000000001100000000000011110011011000001101100000000000000000011000001100110000000000000001111001100110011000000011000000011000000011110011011110000110 0110110110110000000011111110011100001111110000001100000000000011011011011000001101100000000000000000011000001100110000000000000001101101100110001111110001111110011111100011011011001100000111 0110011110110000000000000011001100001100000000001100000000000011001111011000001101100000000000000000011000001100110000000000000001100111100110000000011000000011011000000011001111000000000110 0110001110110000110110000011001100001100000000001100000000000011000111011000001101100000000000000000011000001100110000000000000001100011100110011000011011000011011000000011000111011110000110 0110000110011111100011111110000111101111111100001100001111111011000011001111111001111111101111111000011000011110111111110111111101100001101111001111110001111110011111111011000011011110111100 We then got the flag: NC3{ET_NUL_TIL_NISSEN!