Magnet Weekly CTF – Week 1 – Mapping the Digits

Magnet Forensics have announced a weekly CTF running from October 2020. A new challenge will be released each week on Monday, and the first few are based on an Android filesystem dump.

MD5: 3bb6abb3bf6d09e3e65d20efc7ec23b1
SHA1: 10cc6d43edae77e7a85b77b46a294fc8a05e731d

Let’s go!

Mapping the Digits (20 points)

What time was the file that maps names to IP’s recently accessed?

(Please answer in this format in UTC: mm/dd/yyyy HH:MM:SS)

A pretty simple one to start with. On Linux-based systems (like Android) hostnames are mapped to IP addresses in the /etc/hosts file; find that file in the TAR archive and check the timestamp.

I opened the TAR archive up using FTK Imager, and navigated to the directory containing the hosts file:

/data/adb/modules/hosts/system/etc

There is only one timestamp, but it is worth noting that I have FTK Imager set to display dates in the common European format (day/month/year):

05/03/2020 05:50:18

So swap the day and month values to match the US format required by the question, and we have our first answer.

Flag

03/05/2020 05:50:18

As an aside, confusion around date and timestamps is exactly why we have ISO 8601.

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