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Showing posts from January, 2013

Capturing wifi traffic of one station from another

This is more of an embarrassing tale than a real how-to document. But I found this interesting enough that I don't mind sharing it. A couple of weeks ago I was tasked to capture wifi traffic from a device which didn't have any capture software built in and I wondered how one would do it. I have used sniffing tools on my Mac to passively sniff activity on access points around me. Because I've always tested such tools in places with dozens of access points with multiple saturated channels, I always assumed that all wifi stations ( laptops ) frequently switch channels. I also assumed that AP (Access points) which are setup to select channels automatically are designed to automatically switch channels anytime if they find a better (less noisy) frequency to provide services at. And because of those incorrect assumption, I concluded that sniffing another wifi station would be a difficult task because it would be impossible to dynamically change the channel of a second wifi statio

Capturing wifi traffic of one station from another

This is more of an embarrassing tale than a real how-to document. But I found this interesting enough that I don't mind sharing it. A couple of weeks ago I was tasked to capture wifi traffic from a device which didn't have any capture software built in and I wondered how one would do it. I have used sniffing tools on my Mac to passively sniff activity on access points around me. Because I've always tested such tools in places with dozens of access points with multiple saturated channels, I always assumed that all wifi stations ( laptops ) frequently switch channels. I also assumed that AP (Access points) which are setup to select channels automatically are designed to automatically switch channels anytime if they find a better (less noisy) frequency to provide services at. And because of those incorrect assumption, I concluded that sniffing another wifi station would be a difficult task because it would be impossible to dynamically change the channel of a second wifi statio

Chrome Frame - How to add command line parameters

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Chrome frame intentionally does stuff without getting in the way of the user. This sometimes makes things harder to debug. For example how can one debug an issue if chrome frame doesn't even launch ? Apparently there is a flag for that. But you have to know how to enable it. Here are the steps. Make sure chrome frame is installed. We can enable startup flags for dumping debug logs using a policy called AdditionalLaunchParameters If this is just for one desktop, I recommend doing a registry edit (it can be pushed via GPO as well) Add a REG_SZ property " AdditionalLaunchParameters " to " SoftwarePoliciesGoogleChromeAdditionalLaunchParameters " with the value "--enable-logging --v=1" (also documented here  and mentioned here )  [ Attachment 1 ] Next kill the IE browser and make sure chrome is also dead by checking taskmgr Restart IE and go to " gcf:about:version " and confirm that the parameters you added show up next to "Command Line:"

Chromebooks with Openvpn on EC2

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Chromebooks are perfect companions for travel. They are light, secure and one generally doesn't have to worry about data theft in case they loose the device.  But s urfing from hotels and coffee shops is another story. While most sites are in SSL, there are enough websites which are not... and even the ones which support SSL sometimes forget to use SSL connectivity for sensitive data. Which is why extensions like " HTTPS everywhere " is highly recommended. If I could, I'd pay a few cents for extra level of privacy when using these public wifi networks. In this post I'll document how you could quickly setup an openvpn server on EC2 instance to do exactly this for your chromebook. Prerequisites  A working EC2 account A working key-pair (required to ssh into the EC2 instance) Chromebook with R23 or later  Step 1 - Launch Amazon Linux AMI ( I used 32 bit for my setup.. its the cheapest). Pick all the defaults options and pay attention to which "Security Group&qu

Chromebooks with Openvpn on EC2

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Chromebooks are perfect companions for travel. They are light, secure and one generally doesn't have to worry about data theft in case they loose the device.  But s urfing from hotels and coffee shops is another story. While most sites are in SSL, there are enough websites which are not... and even the ones which support SSL sometimes forget to use SSL connectivity for sensitive data. Which is why extensions like " HTTPS everywhere " is highly recommended. If I could, I'd pay a few cents for extra level of privacy when using these public wifi networks. In this post I'll document how you could quickly setup an openvpn server on EC2 instance to do exactly this for your chromebook. Prerequisites  A working EC2 account A working key-pair (required to ssh into the EC2 instance) Chromebook with R23 or later  Step 1 - Launch Amazon Linux AMI ( I used 32 bit for my setup.. its the cheapest). Pick all the defaults options and pay attention to which "Security Group&qu