Change the login background of Mac OS X

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This story has a history. Way back in early 2000, I wrote a small shellscript that would set the background of the login-screen of XDM (It’s a Xwindows/Unix thing). You can find that original here. I get bored with login-screens that look the same everytime you login – or any desktop background or wallpaper but that’s another story. I figured it shouldn’t be too difficult to change that, it’s an image right? Why shouldn’t I be able to change that. It’s on my computer, shouldn’t I be in control of that? And so a cup of coffee and a little Unix shell code did that trick. The old script depends on Windowmaker to set the background image. I’m not quite sure if that is still around.

So some 10 years later, I convinced my wife that we needed a new computer again, and bought this beautiful, hip & trendy iMac. I’m like a kid in a candy store: This baby runs a decent unix shell and … xman! And I must say that I really like OS X, but being greeted with the same star background over-and-over again when you login gets old pretty quick for me. Continue reading

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File integrity on Mac OS X

Recently the US-CERT released a documented titled “Security Recommendations to Prevent Cyber Intrusions“, which seems to add quite a few measurements to another US official document, but this time in more technical terms. I don’t live in the US, but having a set of recommendations to prevent intrusions on a computer that are originally intended for government purposes, does make me wonder if I could borrow any of them in order to make my computer environment more secure. Continue reading

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Attack from Nmap – The Nmap Scripting Engine

Scripting languages are great. There must be at least a few hundred or maybe even thousand of them. Most popular ones these days start with the letter P. Nmap supports scripts: The Nmap Scripting Engine. This has been around since version 4.21ALPHA1 [2006-12-10]. The Nmap Scripting Engine allows you to use scripts that will be executed when scanning for open ports on a network. Having Nmap executing scripts when scanning is awesome because it potentially allows you to save time NOT having to wait for the complete scan to finish to take further action. Continue reading

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