iForensic is a serie of challenge where the goal is to study an iphone.
Here is the global description of this serie :

As you pass through customs, the customs officer asks you to hand over your phone and its unlock code. The phone is returned to you a few hours later…
Suspicious, you send your phone to ANSSI’s CERT-FR for analysis. CERT-FR analysts carry out a collection on the phone, consisting of a sysdiagnose and a backup.

We are given two tar archives, one containing a backup of the phone and the other what is apparently a crash report.

iCrash Link to heading

Title: iCrash (intro) Points: 25
Number of solves: 661
Description: It seems that a flag has hidden itself in the place where crashes are stored on the phone…

We go to private/var/mobile/Library/Logs/CrashReporter and there is a file called fcsc_intro.txt.

>>> cat fcsc_intro.txt
FCSC{7a1ca2d4f17d4e1aa8936f2e906f0be8}

iDevice Link to heading

Title: iDevice
Points: 100
Number of solves: 602
Description:
To start with, find some information of interest about the phone: iOS version and phone model identifier.
The flag is in the format FCSC{<model identifier>|<build number>}. For example, for an iPhone 14 Pro Max running iOS 18.4 (22E240): FCSC{iPhone15,3|22E240}.

To find these informations I opened the file named Info.plist at the root of the backup which contains informations about the device and found the information I was looking for.

	<key>Build Version</key>
	<string>20A362</string>
    ...
	<key>Product Type</key>
	<string>iPhone12,3</string>

So the flag is FCSC{iPhone12,3|20A362}.