#!/usr/bin/perl
############################################################################
# Given a valid obfuscated string file format, it will quickly print
# out the string "handles", and the unobfuscated strings.
#
# No comments, blank lines or rotation values are printed.
#
###
#
# The string file format is discussed in the obf.pl file and should be
# present in most string files themselves.
#
# If the rotations given are inaccurate, and you really need to know what 
# the real strings are, I've left it as an excersize for you to generate 
# all string rotations possible.  Have fun.
#
###
# 
# Credits: Ideas taken from 
#   http://www.perlmonks.org/index.pl?node_id=385552
#     Thanks to TZapper and Tachyon's posts
#   http://search.cpan.org/author/JUERD/Crypt-Caesar-0.01/Caesar.pm
#   http://search.cpan.org/author/AYRNIEU/Crypt-Rot13-0.6/Rot13.pm
#   http://www.perlmonks.org/index.pl?node_id=421114
#     Thanks to Tanktalus
# 
#-----------------------------------------------------------------------
# Copyright (C) 2005 Scott L. Miller  (scott.l.miller@gmail.com)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
# USA
#-----------------------------------------------------------------------
# Written January, 2005 by Scott L. Miller
#
# Date:
# 01/28/2005  SLM  Initial release
#
############################################################################

sub Usage {
    print <<EOF;
  Usage: $0 <filename>
     or: <someprocess> | $0 

  where: <filename> or piped in text is a "string file" generally 
         containing passwords or SNMP community strings that are
         obfuscated.

         this script will unobfuscate all strings within a correctly
         formated "string file" provided all rotation identification
         numbers for those strings are acurate.

EOF

}

############################################################################
# pwdrot uses the idea of rot13 and expands the characters affected by the
# rotations to include all 94 normal printable ascii characters. 
# ie. chr(33) '!' - chr(126) '~'.  The rotations are thus mod 94.
# 
# Default rotation if not supplied is 47
############################################################################
sub pwdrot {
    my $pwd = shift;
    my $degree = (@_ > 0) ? ((shift) % 94) : 47;

    if ($degree == 0) {
        return $pwd;
    }

    if (length($pwd) == 0) {
        return $pwd;
    }

    $rangestr = "\\" . sprintf("%03lo",$degree+33) . "-\\176\\041-\\" . sprintf("%03lo",$degree+32);

    unless ($pwdrots{$degree}) {
        my $rangstr = "\\" . sprintf("%03lo",$degree+33) . "-\\176\\041-\\" . sprintf("%03lo",$degree+32);
        $pwdrots{$degree} = eval "sub { \$_[0] =~ tr[\041-\176][$rangstr]; }"
    }

    $pwdrots{$degree}->($pwd);

    return $pwd;
}


############################################################################
# Find rotation notations characterized by a decimal number appearing alone 
# on a line, unobfuscate the strings using the given rotation information.
############################################################################
sub process_line {
    s/(^\s+)//; #remove indentation if any
    if(/^$/) { return; } #ignore blank lines
    if(/^#/) { return; } #ignore comments

    chomp;

    my ($result,$handle,$whitespace,$snmpstring);

    ($handle,$whitespace,$snmpstring) = split /(\s+)/;

    if(!defined($snmpstring)) {
        $curdist = int($_);
        return;
    }

    if(!defined($curdist)) {
        print "# Rotation undefined, assuming 0 rotation.\n";
        $curdist = 0;
    }

    $result = pwdrot( $snmpstring, $curdist * -1 );

    print $handle . $whitespace . $result . "\n";

    return;
}

###########################################################################
#  Program begins here
#
# Read "string files" given via the command line, and/or piped in.
###########################################################################

    if( -t && scalar(@ARGV) == 0 ) {
        print "  No file supplied!\n";
        &Usage;
        exit 0;
    }

    local $curdist;

    if(! -t) {
        while(<STDIN>) {
            &process_line;
        }
    }

    if( scalar(@ARGV) > 0 ) {
        while (<>) {
            &process_line;
        }
    }

    exit;