stegbreak(1)

NAME

stegbreak - launches brute-force dictionary attacks on JPG

image

SYNOPSIS

stegdetect  [-qV]  [-r  rules] [-f wordlist] [-t tests] [-c]
[file ...]

DESCRIPTION

The stegbreak states a brute-force dictionary attack against

the specified JPG images.

The options are as follows:

-q Only reports images for which the dictionary

attack succeeded.

-V Displays the version number of the software.

-r rules Contains rules with transformations that will

be applied to the words in the wordlist. The rules follow the

same syntax as in Solar Designers password cracking program John

the Ripper. The default is rules.ini.

-f wordlist Specifies the file that contains the words for

the dictionary attack. The default is /usr/share/dict/words.

-t tests Sets the tests that are being run on the image.

The following characters are understood:

o The dictionary attack follows the

embedding used by outguess.

p The dictionary attack follows the

embedding used by jphide.

j The dictionary attack follows the

embedding used by jsteg-shell.

The default value is p.

-c Specifies that the JPG images should be con

verted to a small sized object that contains all the information

necessary for the dictionary attack. This can be used to reduce

the size of the data set in distributed computing applications.

The stegbreak prints the filename, the embedding system and

the password when the attack succeeded for an image. For jsteg

shell and outguess, it also prints analysis results from the

built in file utility.

Pressing Ctrl-C causes a status line to be displayed, press

ing Ctrl-C a second time within one second aborts the program.

EXAMPLES

stegbreak -t p auto.jpg

Launches a brute-force dictionary attack against auto.jpg

assuming that information has been embedded with jphide.

FILES

/usr/share/dict/words default wordfile for

the dictionary attack.
/usr/local/share/stegbreak/rules.ini rules on how to manip

ulate words for the dictionary attack, from John the Ripper.

SEE ALSO

stegdetect(1)

ACKNOWLEDGEMENTS

This program contains source code from Solar Designer's John

the Ripper. It has been placed under a BSD-license with his per

mission.

This product includes software developed by Ian F. Darwin

and others. The stegbreak utility uses Darwin's file magic to

verify results from OutGuess key guessing.

Korejwa provided information on the data format used by

JSteg Shell.

AUTHORS

The stegbreak utility has been developed by Niels Provos.

BSD July 05, 2001

BSD