Crack, Reporter - programs to break password files
Crack [options] [-fmt format] [file ...]
Crack-Reporter [-quiet] [-html]
This manual page documents briefly the Crack, and Crack-Reporter
commands. This manual page was written for the Debian GNU/Linux
distribution because the original program does not have a manual page.
Instead, there is some documentation available at /usr/share/doc/crack
which you are encouraged to read
Crack is not a program designed to break the password of every user in
the file. Rather, it is designed to find weak passwords in the file,
by attacking those sorts of bad passwords which are most likely to be
used, in the order in which they would most easily be found (ie: are
most likely to be used by a moronic user).
Crack is not designed to break user passwords; it is designed to break
password files. This is a subtle but important distinction.
Crack-Reporter will show what passwords have been cracked, as well as
view errors that have been detected in the source password files, etc.
Guesses are listed chronologically, so users who wish to see
incremental changes in the output as Crack continues to run over a
course of days or weeks, are encouraged to wrap invocations of
Crack-Reporter in a script with diff.
A summary of options are included below. For Crack:
Creates and compresses the dictionaries Crack will use
Compiles the binaries for Crack (not necessary for Debian
GNU/Linux since they are already provided)
-debug Lets you see what the Crack script is doing.
Used when restarting an abnormally-terminated run; suppresses
rebuild of the gecos-derived dictionaries.
-fgnd Runs the password cracker in the foreground, with stdin, stdout
and stderr attached to the usual places.
Specifies the input file format.
Starts password cracking from rule number "N".
-keep Prevents deletion of the temporary file used to store the
password cracker’s input.
-mail E-Mail a warning message to anyone whose password is cracked.
See the script nastygram.
Runs the password cracker in network mode.
Runs the password cracker at a reduced priority, so that other
jobs can take priority over the CPU.
Internal options used to support networking.
For Crack-Reporter -html Produces output in a fairly basic HTML-
readable format. -quiet Suppresses the reporting of errors in
the password file (corrupt entries, etc)
To run Crack
# Crack -nice 10 /etc/passwd
If a Crack session is killed accidentally, it can be restarted with
moderate efficiency by doing:
mv run/Dhostname.N run/tempfilename
Crack -recover -fmt spf run/tempfilename
However if all you wish to do is start cracking passwords from some
specific rule number, or to restart a run whilst skipping over a few
Crack [-recover] -from N filename ...
...where N is the number of the rule to start working from.
/usr/share/Crack Location of the Crack program and scripts.
/var/run/Crack/ Location for the temporary files used by Crack.
You will find more documentation about Crack in the text files
available in /usr/share/doc/crack-common Documentation includes the
program’s Manual (in HTML and Text files), the User’s Frequently Asked
Questions (FAQ), examples, articles and even some humour.
This manual page was written by Javier Fernandez-Sanguino
<firstname.lastname@example.org>, for the Debian GNU/Linux system (but may be used by
Crack and Crack-Reporter (originally called Reporter) were written by
Alec Muffett <Alec.Muffett@UK.Sun.COM>