Remko Weijnen's Blog (Remko's Blog)

About Virtualization, VDI, SBC, Application Compatibility and anything else I feel like


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Recently I stumbled upon an executable that appeared to be a PowerShell script converted into an executable.

I was curious to the actual script so I decided to have a look and see how I could convert the executable back into PowerShell.

Having seen similar techniques to turn vb scripts and java jar’s into executables I first looked if this particular executable was simply carrying the payload in the resource section.

I opened the executable with Resource Hacker and saw 2 resources (note that I am using a simple HelloWorld executable here in the screenshots). The first resource, named 1, is clearly a Unicode string with the title:

Resource Hacker Screenshot showing the resources

Resource Hacker – HelloWorld.exe

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Just a very quick post (more like a note to self) but I wanted to split a string with the $ sign in PowerShell:

Took me a little while to realize that this doesn’t work as the split operator in Windows PowerShell uses a regular expression in the delimiter, rather than a simple character.

The easy fix is to Escape the $ sign with a backslash:

Or alternatively use the SimpleMatch option:

The 0 represents the “return all” value of the Max-substrings parameter. You can use options, such as SimpleMatch, only when the Max-substrings value is specified.

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  • Filed under: PowerShell
  • 4,387 views

    Google Earth LogoBoth Google Earth and Google Earth Enterprise do not work correctly for multiple users on shared Hosted Shared Desktops (I still prefer to call it Server Based Computing but that’s likely because I’m an oldtimer).

    Problem summary
    So let’s look at the actual issue: the first user on a server is able to launch Google Earth but for any subsequent users on the same server Google Earth fails silently.

    Problem details
    Google Earth uses various synchronization objects such as Events and Mutexes but registers those in the \Global namespace instead of the \Local namespace.

     

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    Citrix NetScaler LogoRecently I switched over my blog from a hoster to a self hosted VM. In my setup I am using Citrix NetScaler as a reverse proxy.

    Simular to when you’re using a 3rd party reverse proxy such as CloudFlare you will see the IP address from the reverse proxy instead of the actual Client IP Address on your webserver.

    This means that your logging will all show the same, internal, IP address and that IP Based Access Rules will not work.

    Fortunately this is easy to solve by having NetScaler add the Client IP Address in the headers and rewriting the address on your webserver.

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    When I started this blog in 2007 (wow that’s almost 10 years ago) I went for a cheap web hoster with a reasonable performance to host it.

    In the beginning performance was acceptable but over the years it has degraded and of course user experience standards have changed.

    I decided it was time to do something about it so I’ve moved the blog from a shared platform to my own server.

    This server is running on optimized flash storage  where most writes are DeDuplicated and never actually hits the flash disks:

    image

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    Citrix Receiver and StoreFront error messages are sometimes confusing or lacking details so I decided to make little blog notes about common issues when I see them. So without further ado here’s #1:

    In Citrix Receiver I tried to logon remotely via NetScaler Gateway and got the following error message: “Cannot get your apps from the store

    Cannot get your apps from the store

    Citrix Receiver

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  • Filed under: Citrix
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    If you try to enable “Developer mode” on the VW Discover Pro navigation with VCDS you will get the following error: “Request out of range:”

    VCDS | Discover Pro | Adaptation | Developer Mode | Request out of range

    This happens because VCDS uses a type 0x02 (Programming) session but this adaptation needs type 0x4F (Developer) session.

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  • Filed under: Automotive
  • 836 views

    Today I stumbled upon Shodan, a search engine for devices and services.

    I decided to search for Citrix and this was the first page of results:
    SNAGHTMLf942758

    It’s interesting to see that we get details such as the name of published applications. But it’s possible to get even more details:

    SNAGHTMLf96a047

     

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  • Filed under: General
  • 3,920 views

    When I was trying to delete a folder from my local harddrive (cygwin64 in my case) I got the following error message: “Invalid file handle.“:

    Invalid file handle

    I then attempted to delete the folder from the command prompt which failed as well with an “Access is denied” error:

    image

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    clip_image002

    There has long been a debate about how to accurately view the size of your Citrix Provisioning Services ram cache size. SO much so that even Citrix clarified on how to view this detail using yet another tool

    The thing is, this is all fine and well, but it’s a bit of a pig to actually get this data when you need it, or in an automated way. Wouldn’t it be better if we could have something easier?

    Lately, Andrew Morgan and I decided to sit down and create an easy to use, Windows performance counter for the key metrics in a PVS cache and provide them to the community for use.

    These counters turned out to be fascinating, as they really show how the cache works.

    Our latest counters (which can be downloaded below) provide the following counters for easy access:

    Performance Monitor

    • PVS Ram cache size (MB)
    • PVS metadata size (MB)
    • PVS Write Cache VHD disk size (MB)
    • PVS Ram Cache Percent used. *

    • * As there is no accurate way to detect how much ram is assigned to cache via Citrix Provisioning services, this value must be provided or this performance counter is missing.

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  • Filed under: Citrix
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