Crack, Reporter - programs to break password files
Crack [options] [-fmt format] [file ...]
Crack-Reporter [-quiet] [-html]
This manual page documents briefly the Crack,
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
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.
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
A summary of options are included below. For Crack:
- Creates and compresses the dictionaries Crack will
- Compiles the binaries for Crack (not necessary for
Debian GNU/Linux since they are already provided)
- Lets you see what the Crack script is doing.
- Used when restarting an abnormally-terminated run;
suppresses rebuild of the gecos-derived dictionaries.
- Runs the password cracker in the foreground, with stdin,
stdout and stderr attached to the usual places.
- -fmt format
- Specifies the input file format.
- -from N
- Starts password cracking from rule number
- Prevents deletion of the temporary file used to store the
password cracker's input.
- E-Mail a warning message to anyone whose password is
cracked. See the script nastygram.
- Runs the password cracker in network mode.
- -nice N
- Runs the password cracker at a reduced priority, so that
other jobs can take priority over the CPU.
- -kill filename
- 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 rulesets, try:
Crack [-recover] -from N filename ...
...where N is the number of the rule to start working from.
Location of the Crack program and scripts.
Location for the temporary files used by Crack.
You will find more documentation about Crack in the text files available in
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 Fernández-Sanguino Peña
<email@example.com>, for the Debian GNU/Linux system (but may be used by
(originally called Reporter
written by Alec Muffett <Alec.Muffett@UK.Sun.COM>