kimci86/bkcrack

Attack on .7z stored in a .zip file

VujkePG opened this issue · 2 comments

VujkePG commented

Hi,

I have a 4GB zip file, with 20 files in "ZipCrypto Deflate" method, and a single "ZipCrypto Store" file - a large .7z archive (Size 2.132.596.623, Packed Size 2.132.596.635)

I've compared a number of .7z files in HxD Hex editor, and every single one has 19 identical bytes (sparse), which in theory should make this attack viable:

bkcrack -C archive.zip -c folder/store.7z -x 0 377abcaf271c0004 -x 10 00000000 -x 15 00000000000000

However, no luck. Any suggestions on what am I doing wrong, or maybe an alternative approach?

kimci86 commented

Hi,

After looking at some 7z files, I believe you meant to pass hexadecimal offsets after -x parameters. By default, the offset is parsed as a decimal value. Either pass decimal offsets or add 0x prefix to pass hexadecimal offsets.

Try this:

bkcrack -C archive.zip -c folder/store.7z -x 0 377abcaf271c0004 -x 0x10 00000000 -x 0x15 00000000000000
  • 👍1
VujkePG commented

Worked like a charm! Thank you so much

  • 🎉1