/usr/lib/cgi-bin/samba/smbmsg.pl is in smb2www 980804-41.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 | #! /usr/bin/perl
#  This file smbmsg.pl Copyright 1998 Edward Rudd <eddie@omegaware.com>
#  Modifications by Remco van Mook, 1998.
use strict;
use smb2www;
# Debian: is smb2www enabled?
CheckEnabled() or exit 0;
my %all=decode_query;
sub Message_OK {
  header ("$text{message_ok}", "norefresh");
  print "<CENTER>\n";
  print image($cfg{icon_message},"$text{sendmsg}");
  print "<P>\n";
  print href("$all{back}","$text{goback}")."\n";
  trailer;
}
# my $key = "";
my $back = "";
# foreach $key (keys %all) {
#   $all{$key} = urlDecode $all{$key};
# }
if ($all{'mesg'} eq '') {
  header ("$text{sendmsg}", "norefresh");
  print "<H1>$text{sendmsg2} ";
  if ( $all{'host'} eq '' ) {
    print "$text{workgroup} $all{group}";
  } else {
    print "$all{host}";
  }
  print ":</H1>\n";
  if ($all{'back'} eq '') {
    $back = "$ENV{'HTTP_REFERER'}";
  } else {
    $back = "$all{'back'}";
  }
  print << "EOF" ;
<CENTER><FORM ACTION=\"$cfg{cgiroot}/smbmsg.pl\" METHOD=get>
<TEXTAREA name="mesg" rows=6 cols=50></TEXTAREA><P>
<INPUT type="submit" value="$text{submit}">
<INPUT type="hidden" name="group" value="$all{group}">
<INPUT type="hidden" name="master" value="$all{master}">
<INPUT type="hidden" name="host" value="$all{host}">
<INPUT type="hidden" name="back" value="$back">
</FORM>
EOF
trailer;
} else {
  if ( $all{host} eq '' ) {
    my @smbout = GetSMBHosts ("$all{master}","$all{group}");
    if ( $#smbout < 0 ) {
      header ("$text{no_group}");
      print "<H1>$text{no_group2}</H1><BR>\n";
      table ( 
      href (shref("all"),image ($cfg{icon_all},"$text{network}")),
      "<H3>$text{ent_net}</H3>",
      ""
      );
      trailer;
      exit;
    }
    my $line = "";
    foreach $line ( @smbout ) {
      SendHostMessage ($line->{name},$all{'mesg'});
    }
    Message_OK;
  } else {
    SendHostMessage ($all{'host'},$all{'mesg'});
    Message_OK;
  }
}
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