Helpful Tips From A Mac Systems Administrator

Kerberized

To Fix App Store Updates For Apps You Don’t Have Installed

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A friend recently reported a problem where he was getting update notifications from the Mac App Store (MAS) for programs he did not have installed, under an AppleID that was not his. Since these programs were not installed, he had no way to remove them, and since it was not his AppleID, he had no way to update them. As such, it seemed he was going to be stuck getting these update notifications forever. Luckily, with a little know-how and a lot of persistence, we were able to track down the cause of this and resolve it. In order to understand what is causing this problem, it is important to understand how the MAS keeps track of what you have

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Be Careful What You Copy/Paste

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Given the content of this Blog, and the type of information someone on it would be looking for, I figured I would cover one lesser known vulnerability that SysAdmins often open themselves up to without thinking. This is not a high tech attack vector, but it is an easy one. This attack can occur if you copy/paste commands from a website directly into terminal. I will first show you an example of what happens, then explain how it is happening and how to protect yourself. For simplicity and transparency, we’ll use a command that everyone on this site should understand. Below we are just going to issue the command to change directory to our current user’s desktop. Obviously, you would

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Investigating Strange Network Traffic

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This post is going to be a little bit different than most of my others. It is going to cover the very basic process of analyzing strange network traffic and figuring out what is causing it. I’ll give some background on what I noticed and what our setup was. At the end of this post, I’ll also explain the exact cause of the problem and how to resolve it, in the hopes that I can save someone else some investigation time. This post is not intended to say that this is the only, or even the best, way of finding this information. It is simply the approach I took given our resources and system setup. Having said that, here is

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SSH and SCP Guide

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SSH This guide is going to provide an overview of how to use SSH and SCP to connect to remote computers, run commands, and transfer files to and from them. ssh allows you to have command-line access to other computers over a relatively secure connection. scp lets you copy files to and from another computer over that same secure connection. If you type just ‘ssh’ into the CL you get one of the more obtuse usage messages that I’ve seen: usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec] [-D [bind_address:]port] [-e escape_char] [-F configfile] [-I pkcs11] [-i identity_file] [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port] [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]] [user@]hostname [command] Huh? Before we get too

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My Custom Bash Profile

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This post is a little different than the rest of the items on this site, but I figured I would share. Below is the content of my .profile file that customizes the look of your bash prompt. I do not take credit for everything in it, but I can’t attribute it properly as I have been using this for years and honestly just don’t remember where I pulled all the various bits from. Feel free to use as much or as little of this as you want. I have tried to comment as helpfully as possible. # MacPorts Installer addition on 2012-08-26_at_02:05:52: adding an appropriate PATH variable for use with MacPorts. export PATH=/opt/local/bin:/opt/local/sbin:$PATH # Finished adapting your PATH environment variable

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