zsteg ====== Description ----------- detect stegano-hidden data in PNG & BMP Installation ------------ gem install zsteg Detects: -------- * LSB steganography in PNG & BMP * zlib-compressed data * [OpenStego](http://openstego.sourceforge.net/) * [Camouflage 1.2.1](http://camouflage.unfiction.com/) * [LSB with The Eratosthenes set](http://wiki.cedricbonhomme.org/security:steganography) Usage ----- # zsteg -h Usage: zsteg [options] filename.png [param_string] -c, --channels X channels (R/G/B/A) or any combination, comma separated valid values: r,g,b,a,rg,bgr,rgba,r3g2b3,... -l, --limit N limit bytes checked, 0 = no limit (default: 256) -b, --bits N number of bits, single int value or '1,3,5' or range '1-8' advanced: specify individual bits like '00001110' or '0x88' --lsb least significant BIT comes first --msb most significant BIT comes first -P, --prime analyze/extract only prime bytes/pixels --invert invert bits (XOR 0xff) -a, --all try all known methods -o, --order X pixel iteration order (default: 'auto') valid values: ALL,xy,yx,XY,YX,xY,Xy,bY,... -E, --extract NAME extract specified payload, NAME is like '1b,rgb,lsb' --[no-]file use 'file' command to detect data type (default: YES) --no-strings disable ASCII strings finding (default: enabled) -s, --strings X ASCII strings find mode: first, all, longest, none (default: first) -n, --min-str-len X minimum string length (default: 8) --shift N prepend N zero bits -v, --verbose Run verbosely (can be used multiple times) -q, --quiet Silent any warnings (can be used multiple times) -C, --[no-]color Force (or disable) color output (default: auto) PARAMS SHORTCUT zsteg fname.png 2b,b,lsb,xy ==> --bits 2 --channel b --lsb --order xy Examples -------- ### Simple LSB # zsteg flower_rgb3.png imagedata .. file: 370 XA sysV pure executable not stripped - version 768 b3,rgb,lsb,xy .. text: "SuperSecretMessage" ### Multi-result file # zsteg cats.png meta F .. ["Z" repeated 14999985 times] meta C .. text: "Fourth and last cat is Luke" meta A .. [same as "meta F"] meta date:create .. text: "2012-03-15T23:32:46+07:00" meta date:modify .. text: "2012-03-15T23:32:14+07:00" imagedata .. file: 68K BCS executable b1,r,lsb,xy .. text: "Second cat is Marussia" b1,g,lsb,xy .. text: "Good, but look a bit deeper..." b1,bgr,lsb,xy .. text: "MF_WIhf>" b2,g,lsb,xy .. text: "VHello, third kitten is Bessy" ### wbStego even distributed # zsteg wbstego/wbsteg_noenc_even.bmp 1b,lsb,bY -v imagedata .. file: FoxPro FPT, blocks size 1, next free block index 65537 00000000: 00 01 00 01 00 00 00 01 00 00 00 00 00 00 00 00 |................| 00000010: 00 00 00 00 00 00 00 00 00 00 00 01 00 01 01 00 |................| 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000030: 00 01 01 01 00 01 00 00 00 00 00 00 01 01 00 01 |................| 00000040: 01 00 01 01 00 01 00 01 00 01 01 01 01 00 00 00 |................| 00000050: 00 00 00 01 01 01 01 00 01 00 01 00 00 00 00 01 |................| 00000060: 00 00 01 01 01 00 00 01 00 01 01 01 00 01 00 00 |................| 00000070: 01 01 01 00 01 00 00 00 00 00 01 01 01 00 00 00 |................| 00000080: 00 01 00 01 00 00 01 01 01 01 00 00 00 01 01 00 |................| 00000090: 00 01 00 01 00 01 01 00 01 00 00 01 00 01 00 00 |................| 000000a0: 00 01 01 01 00 01 00 01 01 01 00 01 00 00 00 01 |................| 000000b0: 01 00 01 00 00 01 00 01 00 01 01 01 00 00 00 00 |................| 000000c0: 01 00 00 00 00 01 00 00 01 01 00 00 01 00 00 00 |................| 000000d0: 00 00 01 00 00 01 01 01 00 01 01 00 00 01 00 01 |................| 000000e0: 01 01 01 01 01 01 01 00 00 00 00 00 01 00 00 00 |................| 000000f0: 00 01 01 01 00 00 01 00 00 00 01 01 00 01 00 01 |................| b1,lsb,bY .. <wbStego size=22, data="xtSuperSecretMessage\n", even=true, mix=true, controlbyte="t"> 00000000: 51 00 00 16 00 00 74 0d b5 78 1e a1 39 74 e8 38 |Q.....t..x..9t.8| 00000010: 53 c6 56 94 75 d1 a5 70 84 c8 27 65 fe 08 72 35 |S.V.u..p..'e..r5| 00000020: 1f 3e 53 5d a7 65 8b 6e 3b 63 6b 1d bf 72 ee 27 |.>S].e.n;ck..r.'| 00000030: 65 8d ee 82 74 da 8d 4d b3 8a 06 65 7e f8 73 9c |e...t..M...e~.s.| 00000040: 36 0c 73 aa bd 61 67 29 37 67 5f 0b 06 65 1f a4 |6.s..ag)7g_..e..| 00000050: 0a a1 f8 35 |...5 | ### wbStego encrypted # zsteg wbstego/wbsteg_blowfish_pass_1.bmp 1b,lsb,bY -v b1,lsb,bY .. <wbStego size=26, data="\rC\xF5\xBF#\xFF[6\e\xB3"..., even=false, hdr="\x01", enc="Blowfish"> 00000000: 1a 00 00 00 ff 01 01 0d 43 f5 bf 23 ff 5b 36 1b |........C..#.[6.| 00000010: b3 17 42 4a 3f ba eb c7 ee 9c d7 7a 2b |..BJ?......z+ | ### zlib # zsteg ndh2k12_sp113.bmp -b 1 -o yx -v b1,rgb,lsb,yx .. zlib: data="%PDF-1.4\n%\xC3\xA4\xC3\xBC\xC3\xB6\xC3\x9F\n2 0 obj\n<</Length 3 0 R/Filter/FlateDecode>>\nstream\nx\x9C\x8DT\xC9n\xDB@\f\xBD\xCFW\xF0\x1C \x13\x92\xB3\x03\x86\x80\xC8K\xD1\xDE\\\b\xE8\xA1...", offset=4, size=186 00000000: 00 02 eb 9b 78 9c d4 b9 65 54 24 cc 92 36 58 b8 |....x...eT$..6X.| 00000010: d3 68 e3 ee ee 4e e3 ee ee 0e 85 bb 3b dd 68 23 |.h...N......;.h#| 00000020: 8d bb bb bb 3b 8d bb bb 3b 34 ee 6e 1f ef 7b ef |....;...;4.n..{.| 00000030: 9d 3b b3 e7 cc 9e d9 3d df 9e dd cd 8a 1f 99 19 |.;.....=........| 00000040: 99 55 11 99 4f 58 25 99 82 88 18 1d 13 3d 2b 2c |.U..OX%......=+,| 00000050: 59 6f 7e 6f 7b 6f 63 6f 16 2c 33 21 23 a1 9d 91 |Yo~o{oco.,3!#...| 00000060: 25 2c 2f 2f 83 0c d0 d6 cc d9 9c 90 e5 73 46 89 |%,//.........sF.| 00000070: 41 cc c2 da 19 e8 c8 20 66 6d e8 0c 14 01 1a db |A...... fm......| 00000080: 99 00 f9 f8 60 9d 9c 1d 81 86 36 b0 ee e9 bf 54 |....`.....6....T| 00000090: 86 6d 57 05 e0 3b 26 d5 2f 71 09 51 63 eb c0 82 |.mW..;&./q.Qc...| 000000a0: bf 0f 49 4f 6f e8 40 ff c9 f9 43 25 1d 9e 6b 1b |..IOo.@...C%..k.| 000000b0: a3 73 fd 42 c4 a6 65 3d ef 0a 07 32 17 2d dc f9 |.s.B..e=...2.-..| 000000c0: 10 8c 0d 4b d7 9d e6 01 12 4f 11 6f f0 cd 64 f2 |...K.....O.o..d.| 000000d0: f2 19 5c df 76 eb 01 49 dc fd cd 76 65 a2 3a 8a |..\.v..I...ve.:.| 000000e0: fd bb 13 a9 e6 3a c9 da 19 34 ae f0 43 bb 90 90 |.....:...4..C...| 000000f0: 58 88 de 46 ce 91 6f aa 8d d9 7d b8 d6 88 a6 65 |X..F..o...}....e| See also -------- 1. https://29a.ch/photo-forensics/ 2. https://holloway.nz/steg/ License ------- Released under the MIT License. See the [LICENSE](https://github.com/zed-0xff/zsteg/blob/master/LICENSE.txt) file for further details.