Daily Routine Mac OS

https://trueyfil847.weebly.com/breathing-techniques-mac-os.html. The first one, as outlined in a how-to post at OS X Daily, was to delete a preference file that stored this 2009-vintage iMac’s Bluetooth settings and that had mostly likely gotten corrupted.

I recently attended the awesome SANS DFIR, Mac and iOS Forensics and Incident Response course with Sarah Edwards. This has obviously given me lots of great inspiration on how to negotiate Mac analysis in general and to take a closer look at some of those system files that we covered in training.

  1. Under Mac OS X 10.5 Leopard®, the daily script also prunes the asl.db file that replaced the asl.log file for Apple System Logging. The output from the daily script is written to the /var/log/daily.out file, which can be viewed in Console. By default, the daily script is scheduled to run daily at 03:15 hours local time.
  2. Helping your children establish their own routines in the morning and after school is important for the back to school season. You should plan before school starts but if you are always running for the school bus or find afternoons stressful, it’s never too late to design a routine that fits your family, creates a calm atmosphere.
  3. The daily script removes old log files, “scratch” and “junk” files, backs up the NetInfo database, reports a variety of system and network statistics, and rotates the system.log file. Under OS X 10.4 Tiger and 10.5 Leopard, the daily script also cleans up scratch fax files and prunes asl.log, the log for the Apple System Logging facility.

I’ve spent a little bit of time digging through the log files on my MacBook (Mojave 10.14.2). I’m sure this isn’t new to most practised Unix beards but for those who aren’t aware, there’s a really great little log file called daily.out in /var/log. I had previously given little credence to this log but realised it can be used to determine a whole wealth of useful information. I also reviewed the weekly.out and monthly.out files but these were, in my case, far less granular.

At a high level daily.out contains information relating to disk usage and networking, this file is written at least daily and the configurations for all three of the periodic logs are stored in plist files in the following location:

/System/Library/LaunchDaemons/com.apple.periodic-*****.plistFree golden goddess slots.

After reviewing the content of this file, it made me consider how this might assist in some of my casework?

Disk Usage

Firstly, I borrowed some grep skills from a very knowledgeable and tall colleague on my team to see if we could parse out just some specific information from the daily.out file. We extracted the lines only containing the dates, followed by the lines which related specifically to disk usage.

From this, we were able to find entries dating back as early as 3 months, and that the log contains:

  • Logical volumes mounted at the time entries are written
  • Size of volumes
  • Space used on volumes

As you can imagine, disk volume information will be highly valuable in showing drives or images which were attached when the log was written and especially if you know the volume name used by a device you’re looking to prove access to.

We can also ascertain some other information from this log which is quite valuable.

Bootcamp!

Mac

You may have an instance where a suspect, subject or general bad person is saying they have never used their Bootcamp install, however, you can see from the Bootcamp disk usage that the volume is being written to and from regularly. Perhaps a big chunk of data has been deleted before a date of interest?

Uptime

Daily Routine Mac Os 11

Another interesting piece from the daily.out file is that it will show uptime of the system when the log entries are written. This could help prove whether or not the system was switched on and in use over a specific period.

This may also show some interesting information about account usage on the computer. As Mac computers generally tend to be used by individuals, this means there’s usually only ever one account logged on at any time. If you have an experienced user who is elevating to root every day, then seeing multiple accounts logged on may not be uncommon. Although, if an inexperienced user who has no knowledge of the root account, is logged on many times when another account is logged on, it may be suspicious or warrant further analysis.

Again, we extracted the lines from the daily.out file we are interested in using a simple grep command:

As you can see we can pull some interesting information about computer and account usage:

  • Shows uptime of the system at the point in which the daily.out entry is written
  • Also shows the number of users logged on, remember this is usually going to be one

There are also some very useful network interface statistics listed in this file which are probably more relevant to IR investigations but we may look at these another time.

Daily Routine Mac Os X

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