If you have an Intel-based laptop (Centrino and above) and you’re frequently away from your desk, you might want to check out Notebook Hardware Control. In a nutshell, it’s a Windows application designed to extend your battery life by reducing the power consumption of your laptop’s components.
It does this by allowing you to change various settings in your hardware and software. Obvious things like lowering the brightness of your screen, allowing your hard drive to go to sleep, and clocking down your processor are covered. But there’s other useful features such as the facility to under-volt your processor to consume less energy, and settings to reduce the punch of your graphics processor.
I’ve found I get at least 30 minutes more battery life on my Intel Centrino 1.83Ghz. Try it out, and let me know how much extra battery life you get from it!
After re-installing the OS on a Dell Powervault 715n, I remembered that out of the box, it won’t connect to Windows Update (which is of course really, really stupid for a Windows 2000 Server based NAS).
If you RDC into the box, and then try to connect to Windows Update, you’ll see a message like this:
Access Denied
Network policy settings prevent you from using Windows Update to download and install updates on your computer.
If you believe you have received this message in error, please check with your system administrator.
Solution
To get around this on the 715N, follow these instructions:
Log in as Administrator
Go Start > Run… > gpedit.msc
In the Left pane: Open User Configuration, Administrative Templates, and then click Start Menu and Taskbar
In the Right pane: Double-click on Disable and remove links to Windows Update
Choose ‘Disable’ and click OK
You can now get Windows Updates via the Start Menu
This is pretty cool: Whilst searching for an alternative to HyperTerminal that supports Serial Port connections, I discovered that PuTTY now connects to Serial COM ports as well as the usual SSH/Telnet stuff
As a business you can’t use HyperTerminal Private Edition unless you pay a licence fee; and now that Microsoft has removed HyperTerminal from Windows Vista, finding an Open Source, free-for-commercial-use, replacement for HyperTerminal is invaluable for budget constrained IT departments.
If your Powervault NAS loses network connectivity or won’t boot into the OS, you’ll need to physically access it via the console port at the back. From there you can edit and upgrade the BIOS, run a recovery boot (boots the OS from another drive) and perform hardware diagnostics.
Here’s the settings you’ll need for HyperTerminal:
Bits per second: 115200
Data bits: 8
Parity: None
Stop bits: 1
Flow Control: Xon / Xoff
Every time you deploy a WEP Access Point, a fluffy kitty dies.
Primer
Recently a team of German cryptography researchers perfected methods to recover a WEP key faster than ever before. The older Weak IV attacks generally needed between 500,000 and 2,000,000 packets to recover a 128-bit WEP key. In contrast, the new PTW method needs a mere 85,000 packets to have a 95% chance of recovering the WEP key.
Unlike the Weak IV attack, instead of collecting weak IVs, the PTW method collects ARP requests and responses to attack the encryption. ARP requests can either be collected naturally, or can be generated via packet injection. Until recently, packet injection was only possible in Linux. With the advent of the AirPcap USB adapter, and some unsupported beta drivers, it’s possible to inject packets in Windows. Update: CACE have released AirPcap Tx, which features fully supported packet injection, for an added premium.
In this tutorial, I’ll guide you through the process of recovering a WEP key, via the PTW attack, in Windows. For this you’ll be using the AirPcap USB adapter, Cain, aircrack-ptw, and the aircrack-ng suite.
Legalities
It’s important to point out that these methods should only be applied with permission from the owner of the target AP. You should either be auditing, penetration testing, or demonstrating the weaknesses of WEP in a Test Lab environment. You should not be using these methods to get “Free internet”!
Preparation
You’ll need:
An AP configured with WEP
At least one client associated with the Access Point (to give us an initial ARP request)
Install the beta drivers (or if you have AirPcap Tx, install the drivers from the CD-ROM)
Plug in the AirPcap
Install Cain
Extract aircrack-ng to c:\airpcap\
Extract aircrack-ptw to c:\airpcap\
Move aircrack-ptw.exe to the bin folder (this is no longer required - see my notes)
Optional: To make things easier, move the contents of the bin folder to c:\airpcap\. You’ll then be able to run aircrack-ptw.exe with just c:\airpcap\aircrack-ptw.exe mycapture.cap
Let’s get cracking
I added narration to the video this evening at 20:36. It’s my first attempt at narration, and a little noisy, but I’m sure things will improve as time goes on!
The primary counter measure to this WEP attack is to cease using WEP and switch your Access Points to WPA encryption. As you’ve seen in this video, WEP is just too easy to crack. For further reading, Wikipedia has an excellent entry on WPA.
Access Points are so cheap now that, if your AP doesn’t support WPA via a firmware upgrade, you can easily afford a new one with full WPA or WPA2 support.
Notes
Note 1: After recording this tutorial, I’ve become aware that, as of version 0.9, aircrack-ng.exe natively supports the PTW attack by using the -z switch. For example: aircrack-ng.exe -z mycapturefile.cap. If you want to use this attack, download aircrack-ng from the authors, and replace aircrack-ng.exe in c:\airpcap with the new one.
Note 2: The whole process from starting capture to recovering the WEP key takes about 10 minutes.
Note 3: It is important that you get the Packet Injection drivers and the aircrack-ng release specifically for the AirPcap adapter, or this will not work.
Note 4: Just to summarise the steps in the video:
Run Cain and passively scan for the target AP, making a note of the Channel number.
Using the channel number, tell AirPcap to inject packets once it has collected an ARP request. (You can sometimes force an ARP by sending Deauth. To do that, right click on the client. Otherwise, repair the Wireless connection on the client connected to the AP)
To use the PTW attack, you need to collect all packets. By running airodump-ng you can collect all the packets generated by Cain. The reason we use airodump-ng instead of Cain, is that Cain only collects WEP IVs.
Once you’ve collected enough packets, run aircrack-ptw against the capture file.
Phil is an IT Professional working at DisplayLink in Cambridge,
England. He generally blogs about useful solutions that he comes across in his work/play.
