Stego Workflow

Tip

AWS ํ•ดํ‚น ๋ฐฐ์šฐ๊ธฐ ๋ฐ ์—ฐ์Šตํ•˜๊ธฐ:HackTricks Training AWS Red Team Expert (ARTE)
GCP ํ•ดํ‚น ๋ฐฐ์šฐ๊ธฐ ๋ฐ ์—ฐ์Šตํ•˜๊ธฐ: HackTricks Training GCP Red Team Expert (GRTE) Azure ํ•ดํ‚น ๋ฐฐ์šฐ๊ธฐ ๋ฐ ์—ฐ์Šตํ•˜๊ธฐ: HackTricks Training Azure Red Team Expert (AzRTE)

HackTricks ์ง€์›ํ•˜๊ธฐ

๋Œ€๋ถ€๋ถ„์˜ stego ๋ฌธ์ œ๋Š” ๋ฌด์ž‘์œ„ ๋„๊ตฌ๋ฅผ ์‹œ๋„ํ•˜๊ธฐ๋ณด๋‹ค ์ฒด๊ณ„์ ์ธ triage๋กœ ๋” ๋น ๋ฅด๊ฒŒ ํ•ด๊ฒฐ๋ฉ๋‹ˆ๋‹ค.

ํ•ต์‹ฌ ํ๋ฆ„

๋น ๋ฅธ triage ์ฒดํฌ๋ฆฌ์ŠคํŠธ

๋ชฉํ‘œ๋Š” ๋‘ ๊ฐ€์ง€ ์งˆ๋ฌธ์— ํšจ์œจ์ ์œผ๋กœ ๋‹ตํ•˜๋Š” ๊ฒƒ์ž…๋‹ˆ๋‹ค:

  1. ์‹ค์ œ container/format์€ ๋ฌด์—‡์ธ๊ฐ€?
  2. payload๊ฐ€ metadata, appended bytes, embedded files์— ์žˆ๋Š”๊ฐ€, ์•„๋‹ˆ๋ฉด content-level stego์— ์žˆ๋Š”๊ฐ€?

1) Identify the container

file target
ls -lah target

๋งŒ์•ฝ file๊ณผ ํ™•์žฅ์ž๊ฐ€ ์ผ์น˜ํ•˜์ง€ ์•Š์œผ๋ฉด, file์„ ์‹ ๋ขฐํ•˜๋ผ. ์ ์ ˆํ•œ ๊ฒฝ์šฐ ์ผ๋ฐ˜ ํ˜•์‹์„ ์ปจํ…Œ์ด๋„ˆ๋กœ ์ทจ๊ธ‰ํ•˜๋ผ (์˜ˆ: OOXML ๋ฌธ์„œ๋Š” ZIP ํŒŒ์ผ์ด๋‹ค).

2) ๋ฉ”ํƒ€๋ฐ์ดํ„ฐ์™€ ๋ช…๋ฐฑํ•œ ๋ฌธ์ž์—ด์„ ์ฐพ์•„๋ผ

exiftool target
strings -n 6 target | head
strings -n 6 target | tail

์—ฌ๋Ÿฌ ์ธ์ฝ”๋”ฉ์„ ์‹œ๋„ํ•˜์„ธ์š”:

strings -e l -n 6 target | head
strings -e b -n 6 target | head

3) ์ถ”๊ฐ€๋œ ๋ฐ์ดํ„ฐ / ํฌํ•จ๋œ ํŒŒ์ผ ํ™•์ธ

binwalk target
binwalk -e target

์ถ”์ถœ์ด ์‹คํŒจํ–ˆ์ง€๋งŒ ์‹œ๊ทธ๋‹ˆ์ฒ˜๊ฐ€ ๋ณด๊ณ ๋˜๋ฉด, dd๋กœ ์˜คํ”„์…‹์„ ์ˆ˜๋™์œผ๋กœ ์นด๋น™ํ•œ ๋‹ค์Œ ์นด๋น™ํ•œ ์˜์—ญ์— ๋Œ€ํ•ด file์„ ๋‹ค์‹œ ์‹คํ–‰ํ•˜์„ธ์š”.

4) ์ด๋ฏธ์ง€์ธ ๊ฒฝ์šฐ

  • ์ด์ƒ ์ง•ํ›„ ๊ฒ€์‚ฌ: magick identify -verbose file
  • PNG/BMP์ธ ๊ฒฝ์šฐ, ๋น„ํŠธ ํ‰๋ฉด/LSB ์—ด๊ฑฐ: zsteg -a file.png
  • PNG ๊ตฌ์กฐ ๊ฒ€์ฆ: pngcheck -v file.png
  • ์ฑ„๋„/ํ‰๋ฉด ๋ณ€ํ™˜์œผ๋กœ ๋‚ด์šฉ์ด ๋“œ๋Ÿฌ๋‚  ์ˆ˜ ์žˆ๋Š” ๊ฒฝ์šฐ ์‹œ๊ฐ์  ํ•„ํ„ฐ(Stegsolve / StegoVeritas)๋ฅผ ์‚ฌ์šฉํ•˜์„ธ์š”

5) ์˜ค๋””์˜ค์ธ ๊ฒฝ์šฐ

  • ๋จผ์ € ์ŠคํŽ™ํŠธ๋กœ๊ทธ๋žจ ํ™•์ธ (Sonic Visualiser)
  • ์ŠคํŠธ๋ฆผ ๋””์ฝ”๋“œ/๊ฒ€์‚ฌ: ffmpeg -v info -i file -f null -
  • ์˜ค๋””์˜ค๊ฐ€ ๊ตฌ์กฐํ™”๋œ ํ†ค์ฒ˜๋Ÿผ ๋ณด์ด๋ฉด DTMF ๋””์ฝ”๋”ฉ์„ ์‹œํ—˜ํ•ด๋ณด์„ธ์š”

๊ธฐ๋ณธ ๋„๊ตฌ

์ด ๋„๊ตฌ๋“ค์€ ๋ฉ”ํƒ€๋ฐ์ดํ„ฐ ํŽ˜์ด๋กœ๋“œ, ์ถ”๊ฐ€๋œ ๋ฐ”์ดํŠธ, ํ™•์žฅ์ž๋กœ ์œ„์žฅํ•œ ์ž„๋ฒ ๋””๋“œ ํŒŒ์ผ ๋“ฑ ์ปจํ…Œ์ด๋„ˆ ์ˆ˜์ค€์—์„œ ์ž์ฃผ ๋ฐœ์ƒํ•˜๋Š” ๊ฒฝ์šฐ๋ฅผ ์žก์•„๋ƒ…๋‹ˆ๋‹ค.

Binwalk

binwalk file
binwalk -e file
binwalk --dd '.*' file

Foremost

foremost -i file

ํŒŒ์ผ ๋‚ด์šฉ ์ „์ฒด๋ฅผ ๋ฐ›์ง€ ๋ชปํ–ˆ์Šต๋‹ˆ๋‹ค. src/stego/workflow/README.md์˜ ๋ฒˆ์—ญ์„ ์›ํ•˜์‹œ๋ฉด ํ•ด๋‹น ํŒŒ์ผ์˜ ๋‚ด์šฉ์„ ๋ถ™์—ฌ ๋„ฃ์–ด ์ฃผ์„ธ์š”.

์ฐธ๊ณ : ํ˜„์žฌ ์ œ๊ณตํ•˜์‹  ํ•œ ์ค„(#### Exiftool / Exiv2)์€ markdown ํ—ค๋”์™€ ํˆด ์ด๋ฆ„์„ ํฌํ•จํ•˜๋ฏ€๋กœ ๊ทœ์น™์— ๋”ฐ๋ผ ๋ฒˆ์—ญํ•˜์ง€ ์•Š๊ณ  ๊ทธ๋Œ€๋กœ ์œ ์ง€ํ•ด์•ผ ํ•ฉ๋‹ˆ๋‹ค.

exiftool file
exiv2 file

ํŒŒ์ผ / ๋ฌธ์ž์—ด

file file
strings -n 6 file

cmp

cmp original.jpg stego.jpg -b -l

์ปจํ…Œ์ด๋„ˆ, ์ถ”๊ฐ€๋œ ๋ฐ์ดํ„ฐ ๋ฐ polyglot tricks

๋งŽ์€ steganography challenges๋Š” ์œ ํšจํ•œ ํŒŒ์ผ ๋’ค์— ๋‚จ์•„ ์žˆ๋Š” ์ถ”๊ฐ€ ๋ฐ”์ดํŠธ์ด๊ฑฐ๋‚˜ ํ™•์žฅ์ž๋กœ ์œ„์žฅ๋œ ์ž„๋ฒ ๋””๋“œ ์•„์นด์ด๋ธŒ์ž…๋‹ˆ๋‹ค.

Appended payloads

๋งŽ์€ ํฌ๋งท์€ ํ›„ํ–‰ ๋ฐ”์ดํŠธ๋ฅผ ๋ฌด์‹œํ•ฉ๋‹ˆ๋‹ค. ZIP/PDF/script๊ฐ€ ์ด๋ฏธ์ง€/์˜ค๋””์˜ค ์ปจํ…Œ์ด๋„ˆ์— ๋ง๋ถ™์—ฌ์งˆ ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.

๋น ๋ฅธ ํ™•์ธ:

binwalk file
tail -c 200 file | xxd

offset์„ ์•Œ๊ณ  ์žˆ๋‹ค๋ฉด dd๋กœ carveํ•˜์„ธ์š”:

dd if=file of=carved.bin bs=1 skip=<offset>
file carved.bin

๋งค์ง ๋ฐ”์ดํŠธ

file ๋ช…๋ น์ด ํ˜ผ๋™๋  ๋•Œ, xxd๋กœ ๋งค์ง ๋ฐ”์ดํŠธ๋ฅผ ํ™•์ธํ•˜๊ณ  ์•Œ๋ ค์ง„ ์‹œ๊ทธ๋‹ˆ์ฒ˜๋“ค๊ณผ ๋น„๊ตํ•˜์„ธ์š”:

xxd -g 1 -l 32 file

Zip-in-disguise

ํ™•์žฅ์ž๊ฐ€ zip๋ผ๊ณ  ๋ช…์‹œ๋˜์–ด ์žˆ์ง€ ์•Š์•„๋„ 7z์™€ unzip์„ ์‹œ๋„ํ•ด๋ณด์„ธ์š”:

7z l file
unzip -l file

stego ์ธ๊ทผ์˜ ์ด์ƒ ํ˜„์ƒ

stego ์˜†์— ์ž์ฃผ ๋‚˜ํƒ€๋‚˜๋Š” ํŒจํ„ด์— ๋Œ€ํ•œ ๋น ๋ฅธ ๋งํฌ (QR-from-binary, braille ๋“ฑ).

QR codes from binary

blob ๊ธธ์ด๊ฐ€ ์™„์ „ ์ œ๊ณฑ์ˆ˜์ด๋ฉด ์ด๋ฏธ์ง€/QR์˜ ์›์‹œ ํ”ฝ์…€์ผ ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.

import math
math.isqrt(2500)  # 50

Binary-to-image ๋ณ€ํ™˜ ๋„๊ตฌ:

์ ์ž

์ฐธ๊ณ  ๋ชฉ๋ก

Tip

AWS ํ•ดํ‚น ๋ฐฐ์šฐ๊ธฐ ๋ฐ ์—ฐ์Šตํ•˜๊ธฐ:HackTricks Training AWS Red Team Expert (ARTE)
GCP ํ•ดํ‚น ๋ฐฐ์šฐ๊ธฐ ๋ฐ ์—ฐ์Šตํ•˜๊ธฐ: HackTricks Training GCP Red Team Expert (GRTE) Azure ํ•ดํ‚น ๋ฐฐ์šฐ๊ธฐ ๋ฐ ์—ฐ์Šตํ•˜๊ธฐ: HackTricks Training Azure Red Team Expert (AzRTE)

HackTricks ์ง€์›ํ•˜๊ธฐ