Continuing on with our VPN series I find it important to highlight the weaknesses in the protocols we have talked about thus far. In my last segment I highlighted a tool that allows an attacker to easily hijack an SSL session using a man-in-the-middle attack. Couple this with Adito (aka OpenVPN-ALS), my favorite open-source SSL VPN server, and you can see the problem.

But what about the basic Microsoft VPN we setup a few weeks back? The VPN servers that we setup on Windows XP and Server 2003 used either active directory or local windows accounts to authenticate users.

And looking back at our discussions on pwdump, rainbow tables and the like you’ll remember the inherent weaknesses in Windows account credentials.

There are two ways Windows stores a user’s account credentials, or password. LAN Manager hashes which are comprised of watered-down weaksauce and NTLM which are succeptable to time-memory tradeoff attacks.

The default VPN server implemented in Windows XP and Server 2003’s Routing and Remote Access service uses Point-To-Point-Tunneling-Protocol. This is convenient because the Windows clients have supported Microsoft PPTP VPN connections natively since 2000, and in Windows 95/98 with Dual Up Networking version 1.3.

The modern authentication protocol of Microsoft’s PPTP is MS-CHAPv2. This Challenge Handshake Authentication Protocol suffers from inherent weaknesses.

As far back at 1999 these weaknesses have been widely known. If you’re interested in reading more on the cryptanalysis of MS-CHAPv2 there’s a nifty paper written by Bruce Schneier and L0pht that I’ll link in the show notes.

And while other options exist such as Radius, this is still the default option for PPTP authentication in Windows environments.

Joshua Wright, author of coWPAtty (See our segment here), released in 2004 a proof of concept tool to demonstrate weaknesses in LEAP and PPTP protocols.

This tool, ASLEAP, was updated in 2007 to include an option to just crack MS-CHAP v2. Either by examining a packet capture that includes a MS-CHAP handshake ASLEAP or specifying an MS-CHAP challenge and response ASLEAP is able to deduce the username and last two bytes of the NT hash. Using this information, and a dictionary file, ASLEAP is able to brute-force the hash.

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Continuing on with our VPN series I find it important to highlight the weaknesses in the protocols we have talked about thus far. In my last segment I highlighted a tool that allows an attacker to easily hijack an SSL session using a man-in-the-middle attack. Couple this with Adito (aka OpenVPN-ALS), my favorite open-source SSL VPN server, and you can see the problem.

But what about the basic Microsoft VPN we setup a few weeks back? The VPN servers that we setup on Windows XP and Server 2003 used either active directory or local windows accounts to authenticate users.

And looking back at our discussions on pwdump, rainbow tables and the like you’ll remember the inherent weaknesses in Windows account credentials.

There are two ways Windows stores a user’s account credentials, or password. LAN Manager hashes which are comprised of watered-down weaksauce and NTLM which are succeptable to time-memory tradeoff attacks.

The default VPN server implemented in Windows XP and Server 2003’s Routing and Remote Access service uses Point-To-Point-Tunneling-Protocol. This is convenient because the Windows clients have supported Microsoft PPTP VPN connections natively since 2000, and in Windows 95/98 with Dual Up Networking version 1.3.

The modern authentication protocol of Microsoft’s PPTP is MS-CHAPv2. This Challenge Handshake Authentication Protocol suffers from inherent weaknesses.

As far back at 1999 these weaknesses have been widely known. If you’re interested in reading more on the cryptanalysis of MS-CHAPv2 there’s a nifty paper written by Bruce Schneier and L0pht that I’ll link in the show notes.

And while other options exist such as Radius, this is still the default option for PPTP authentication in Windows environments.

Joshua Wright, author of coWPAtty (See our segment here), released in 2004 a proof of concept tool to demonstrate weaknesses in LEAP and PPTP protocols.

This tool, ASLEAP, was updated in 2007 to include an option to just crack MS-CHAP v2. Either by examining a packet capture that includes a MS-CHAP handshake ASLEAP or specifying an MS-CHAP challenge and response ASLEAP is able to deduce the username and last two bytes of the NT hash. Using this information, and a dictionary file, ASLEAP is able to brute-force the hash.

PS: Check out Player2Rentals.com.

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Cracking WPA Keys with Cowpatty

A lot has changed since I last talked about WPA Cracking on Hak5. Specifically Joshua Wright, author of CowPatty has released a new version that dramatically changes the way one thinks about cracking WPA and WPA2 TKIP keys.

The most notable new feature in Cowpatty 4.5 is the “-2″ option, which only requires the first two frames of the 4-way handshake to start attacking.

By removing the need for the third and fourth frames of the handshake, an attacker is now more likely to successfully crack WPA keys when channel hopping. Furthermore, the lack of the third and fourth frame opens up a world of possabilities when it comes to trapping targets with rogue access points, or “honey pots”.

An example scenario illustrated on Wright’s blog details how an attacker may pose as a victim’s corporate wireless access point. Since it doesn’t matter if the target associates with the honey pot, anything from hostap to a spare WPA supporting access point with a bogus key will due.

Of course this has our friend Robin Wood pondering a Jasager plugin. Pineapples anyone?

As for carrying out the attack it’s pretty straight forward. I BackTrack as my hacking OS of choice coupled with an eee PC or Acer Aspire One. When it comes to Wireless I’m a big fan of the ALFA AWUS036H 500mW USB Wireless Adapter.

Other tools needed to carry out the attack include WPA tables like these SSID specific Cowpatty WPA Tables from Offensive Security and the Aircrack-ng suite.

The commands are pretty straight forward and well highlighted in the episode. There are a number of ways to go about this so if you’ve got another method you’d like to share with me, questions about this, or suggestions for future topics drop me a line. darren[at]hak5=dot=org.

Excerpt Darren Kitchen’s blog

ESXi & iSCSI

So the series I’ve been doing on ESXi has been getting nothing but great feedback, and I’m glad that I can share what I’ve learned over the course of the last couple years with everyone.

On episode 518 of Hak5, we show how truly easy it is to add iSCSI storage to a free deployment of ESXi.

So what is iSCSI?

In computing, iSCSI (pronounced /??s’k?zi/), is an abbreviation of Internet Small Computer System Interface, an Internet Protocol (IP)-based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances. iSCSI can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet and can enable location-independent data storage and retrieval. The protocol allows clients (called initiators) to send SCSI commands (CDBs) to SCSI storage devices (targets) on remote servers. It is a popular storage area network (SAN) protocol, allowing organizations to consolidate storage into data center storage arrays while providing hosts (such as database and web servers) with the illusion of locally-attached disks. Unlike traditional Fibre Channel, which requires special-purpose cabling, iSCSI can be run over long distances using existing network infrastructure.

In simpler terms, using some free software, it’s stupid easy to create a large amount of storage which is not tied to the physical adapter of the host server (in this case, the server ESXi is running on).

So what do we need?

• Functioning ESXi Installation
• Server capable of running FreeNAS
• Gigabit connectivity between ESXi server and FreeNAS

Now let’s get started. While it’s recommended to separate your iSCSI traffic from your other internet networking, for the purpose of this instruction, we’re just going to use the same IP subnet for all of our LAN and iSCSI traffic.

Our ESXi server sits at 10.10.1.55 and our newly installed FreeNAS server is located at 10.10.1.66

1. Connect to your FreeNAS server through the WebGUI using your favorite browser. In the top menu select Disks, then click Management.
2. Click on the plus sign in the lower right corner to add drives.
3. Next to Disk, choose the drive you want to add from the drop down, and if you want enter a description for it next to Description.
4. When you go back to the Disk Management screen you will be asked to confirm the addition by clicking on Apply changes, go ahead and do that now.
5. From the top menu choose Services, then iSCSI Target.
6. Click on the plus sign in the Extent area.
7. The Bolded fields are required, so place a name in the Extent name field, leave the Type as Device, and then choose the Device you want in the dropdown.
8. When you get back to the iSCSI Target page click on Apply changes.
9. Click on the plus sign in the Target area.
10. As before the Bolded fields are required. Here is a breakdown of the fields:

    Target name: Add your own or leave the default
    
    Flags: RW for Read/Write or RO for Read Only
    
    Storage: Will have the extents listed that were setup, choose the one you want to use
    
    Authorized Network: Enter the IP network that can access this drive. For us we’re going to enter 10.10.1.0 and we’ll leave the /24 as our subnet is 255.255.255.0

    Once you fill in all the info click on Add.

11. Back at the iSCSI target page you need to click on Apply changes once again.
12. Now place a check in the box next to Enable in the top right corner and then click Save and Restart in the bottom left.
13. The iSCSI Target drive is now setup and ready for use.

Now we need to setup ESXi to connect to our newly created iSCSI target.

Start by logging into your your host by using the Vitrual Infrastructure Client.

Click on your host, and then click the configuration tab.

Click Storage adapters, and then select your VMHBA32 iSCSI storage adapter.

Click properties and configure, then check the enabled box.

Goto the dynamic discovery tab, and add your FreeNAS IP address (in this case, 10.10.1.66)

Click ok, then close, and then rescan the HBA.

At this point you should see your storage, now we need to format the new storage.

So click back to the storage option on the left.

Then click Add Storage.

Select Disk / Lun, and click next.

Select your new disk on the FreeNAS iSCSI target, and next, next, finish.

DONE!

Questions? Post em in the comments!

Excerpt Matt Lestock’s blog

Bypass Windows Local Logins

Kon-Boot

Kon-Boot is an prototype piece of software which allows to change contents of a linux kernel (and now Windows kernel also!!!) on the fly (while booting). In the current compilation state it allows to log into a linux system as ‘root’ user without typing the correct password or to elevate privileges from current user to root. For Windows systems it allows to enter any password protected profile without any knowledge of the password. It was acctually started as silly project of mine, which was born from my never-ending memory problems Secondly it was mainly created for Ubuntu, later i have made few add-ons to cover some other linux distributions. Finally, please consider this is my first linux project so far Entire Kon-Boot was written in pure x86 assembly, using old grandpa-geezer TASM 4.0.

So basically, Kon-Boot enables you to log into any Windows or Linux password protected computer without knowing the password or anything about it.

The tech behind it? Kon-Boot basically latches onto parts of the memory and starts patching parts of the kernel (the Brain!), mainly the parts that have to do with the log-on auth and security. These patches let you logon without a password. Then, the bootkit does it so quickly that it leaves no footprints behind after you leave.

DUDE!

To do this:

Go to the website above and download Kon-Boot, open the zip file, and burn the .iso to a disc. I use ImgBurner because it is fast, easy, and FREE.

Shut down the computer you intend to get on to. When booting up, if it isn’t already set to boot from CD (or flashdrive, or whatever Kon-Boot is on), go into the BIOS and set it. You should see the Kon-Boot splash screen for a few seconds, then the username/password screen will appear with the main username already set if they have it saved. If not you need to know the username ahead of time. Press enter or type in some random characters (it doesn’t really matter) and press enter. You’re in!

Now party, snoop around, and get that file you wanted. Get your flashdrive or CD out, then shut the computer back off like usual.

Protecting yourself:

Password protect your BIOS!

True Crypt your entire harddrive!

Excerpt Shannon Morse’s blog

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In an effort to thwart hangovers the gang drops by DC’s Taven in Hoboken to geek out about Wifi and Virtualization over shots and cold ones.

Darren is excited about the recent improvements to both Airpwn and Cowpatty.

Edit: Mubix points out these awesome WPA Tables from Offensive-Security (You know ‘em as the BackTrack guys).

Best WPA Tables out there for us with CoWPAtty. (And another little + is they posted the password list they used to generate the tables, which is also an AWESOME password list for cracking all kinds of passwords.

Matt answers some viewers questions and encourages more for an upcoming special.

Shannon has all the deets on this week’s contest and LAN party.

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Show Notes

Common User Password Profiler

The Common User Password Profiler from Remote-Exploit is a password/passphrase generator specifically targeted as an individual user. Feed it some info like names, birth dates, spouce, children and pets and it will generate individually, or along with an existing dictionary, thousands of potential passwords. Just add water, feed to your favorite brute forcer and enjoy.

From personal experience I can vouch that, while simple sounding, this would have a HIGH success rate on some of my _former_ (L)users. Administrators take note and enforce BOFH password requirements

netcat – “The Swiss-army knife for TCP/IP”

When it comes to sending and receiving TCP and UDP any which way from the console nothing is more versatile or easy to use than netcat.

With a few simple commands you can use netcat to initiate chat, file transfer or even shell access in either direction between a “server” and a “client”.

The tool can be set to listen or broadcast on any port and tied together with some shell-fu almost anything is possible.

Some listener favorites include cloning hard drives over a network with dd and netcat, tailing a log across the network, port scanning, IP redirecting, or even spoofing user-agents and referrers. Internet Explorer 22 anyone?

Digininja points to this great netcat cheat sheet (PDF 128K).

What kind of crazy stuff have you done with netcat? Feedback@hak5.org

Shannon’s Wordpress Plugin Picks

Twitme

This plugin allows you to automatically post your new posts on the twitter website. This is good because the iPod and iPhone for example have a large amount of twitter clients to pick from. Your blog posts will arrive to people while they are walking the streets.

Socialite

Socialite allows your Wordpress posts to publish to Twitter, Facebook, and MySpace. Each social networking site can be enabled or disabled for publishing, and each is configured separately with their own options. Support for Short URL services such as zz.gd and Tinyurl.com is also supported.

Sociable

Automatically add links to your favorite social bookmarking sites on your posts, pages and in your RSS feed. You can choose from 99 different social bookmarking sites!

MobilePress

MobilePress is a WordPress plugin that will render your WordPress blog on mobile handsets, with the ability to use customized themes. The plugin also allows specific themes for specific devices / mobile browsers, such as iPhone, Opera Mini, Windows CE Mobile and other generic handset browsers.

Resize at Upload Plus

The plugin will automatically resize an image upon upload, depending on the maximum width and height that you define. Gone are the days when you, or your client, will ruin a site’s layout by uploading a huge file with 25 megapixels. Be advised: there is no backup, no copy of the originally uploaded image.

WP-Cache 2.0

WP-Cache is an extremely efficient WordPress page caching system to make your site much faster and responsive. It works by caching Worpress pages and storing them in a static file for serving future requests directly from the file rather than loading and compiling the whole PHP code and then building the page from the database. WP-Cache allows to serve hundred of times more pages per second, and to reduce the response time from several tenths of seconds to less than a millisecond.

Wordpress Backup

Backup the upload directory (images), current theme directory, and plugins directory to a zip file. Zip files optionally sent to email.

WP Security Scan

Scans your WordPress installation for security vulnerabilities and suggests corrective actions.

WP Ban

It will display a custom ban message when the banned IP, IP range, host name or referer url trys to visit you blog. You can also exclude certain IPs from being banned. There will be statistics recordered on how many times they attemp to visit your blog. It allows wildcard matching too.

pixelstats

Count every viewer and every article view for each blog entry, no matter how and where it is read: pixelstats tracks views of each blog post or page, not only on a single article page but also on each other page where the complete article is shown, i.e. the blog front page, category pages, search result page, archive pages and even RSS fee

Thanks for watching, subscribing, and most of all supporting the show. Custom commissioned WiFi Pineapples running Jasager are still available.

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Show Notes

Online Brute Force Countermeasures And Chicken Noodle Soup

Similar in function to SSH, Remote Desktop Protocol is one of the essential tools for administrating Microsoft Windows Servers. The natively encrypted services comes standard on Windows Server and even XP Pro and Vista. It is also serve as the example for a brief followup to my previous segment on Offline Brute Forcing.

In my scenario I demonstrate how the tool TSGrinder can be used to perform dictionary attacks against RDP services with character substitution (or leet) options. This attack simply demonstrates a few weeknesses in Windows.

First of all by default the Administrator account cannot be locked out remotely. This behavior can be changed using the Passprop utility from the Windows 2000 resource kit. This tool will also allow you to enforce strong passwords. It is also recommended that the administrator account be renamed. There are a few tools for this as well. Though more obscurity than security I recommend changing the RDP listen port. I strongly recommend reviewing Microsoft’s password best practices and considering passphrases. PasswordMeter.com is a nice site that will rate your password on complexity. Finally I recommend enabling extensive auditing. There are a number of third party security applications made specifically for auditing that offer alerting options on events such as online brute force attempts. One application in particular, 2X SecureRDP offers advanced filtering based on IP and Mac addresses for RDP connections. I’m particularly interesting in hearing your feedback on Windows extensive auditing software so please drop me a line, darrenAThak5.0rg!

And my final recommendation on securing RDP is to limit its exposure by keeping TCP 3389 (or whatever port you’ve changed it to) closed. A little SSH tunneling or VPNing can go a long way to keeping unncessary serices away from the wild wild web. I’ve laid the foundation for this in a segment on 1×07 and will follow up with a more robust VPN segment soon. If you’ve got ideas again drop me a line.

–Darren Kitchen

Terminal Service Alternatives

The website is located at http://www.xpunlimited.nl there is a large list of benefits at http://xpunlimited.nl/benefits.html

One of the really nice features is the ability to repurpose an old XP machine to use as a terminal server.

The setup couldn’t be easier, and is pretty much a standard application installer, customization is a very simple process from limiting application launches, to customizing the initial desktop, and even advanced functions which replicate the microsoft terminal services security settings.

Questions or alternatives?

–Matt Lestock

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Show Notes

MD5 Brute Forcing with your graphics card

Since Nvidia released the CUDA API for Windows, Mac and Linux a number of advances have taken place in the world of brute forcing. In this episode I feature a tool by Svarychevski Michail Aleksandrovich that claims to be the world’s fastest MD5 cracker — BarsWF

Using the brute forcer with a couple Nvidia 8 series or newer graphics cards you’re able to achieve unprecidented speeds. I’ve seen claims of nearly 4 billion hashes per second with quad SLI.

CUDA has also spurred other developments, such as this NTLM brute forcer for Linux.

In my segment I go into the very basics of password cracking theory and MD5 hashes with some simple scenarios. My aim is to provide a fundamental understanding of the concepts. If you’re interested in reading more I suggest starting here.

–Darren Kitchen

Windows Password Recovery with Ophcrack Live USB

Recovering Windows Passwords coulnd’t be easier with Ophcrack Live on USB. Whether it’s your sister’s forgotten XP account or [insert other legit reason] a little USB booting and Rainbow Table loving’s got you covered.

Preparing an Ophcrack USB key is as simple as formatting your drive for FAT32 with the HP USB format tool. Downloading and launching USBOphcrack.exe and running the included batch file. The program will download a small set of rainbow tables and prepare your USB drive.

For even higher password recovering accuracy I recommend finding a larger set of Ophcrack compatible rainbow tables. Or if you’re feeling adventerous why not try out the Hak5 community rainbow tables — a whopping 120GB of NTLM goodness.

–Shannon Morse

Be sure to follow one of us on Twitter if you’ll be at CES this week. We’ll be there finding all the best hackable gadgets!

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