Home Cellebrite Fall 2020 CTF - Part 4 - Ruth Langmore
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Cellebrite Fall 2020 CTF - Part 4 - Ruth Langmore

Ruth Langmore’s iPhone X (D221AP)

Application Analysis - 10 points

On what date did Ruth want to be reminded to “Move the product”? (answer MM-DD-YYYY)

Cellebrite provides parsed reminder information under Analyzed Data > Calander > Reminders. In this table, a reminder with the title “Move the product can be seen”.

Reminder

The date the reminder is set for in the format required by the solution is 08-14-2020.

Browser History - 10 points

Where did Ruth look up weather forecasts for? (answer must include city and state in this format - Washington, DC)

The Web History tab can reveal the solution to this question. Searching for the term “weather” reveals several AccuWeather website visits, with the city and state visible.

Weather search

The solution to this challenge is Carolina Beach, NC.

Communications - 10 points

Who is the owner/creator of the group named “OG Crew” across the devices?

Searching the image for “OG Crew” returns the Telegram conversation.

Telegram conversation

The initial message includes a PeerId listed as 953301191. Checking the details of the conversation, we can see user PeerIds.

Tony M PeerId

The PeerId is listed as Tony M’s id. The fact he made the first message supports him creating the group, as well as changing the group photo in the second message.

Inputting Tony M reveals it is indeed the correct answer.

Device Identification - 20 points

Which iOS version was running on the device at the time of acquisition? (answer with just the number - i.e. 12.3)

The currently running iOS version can simply be found in the plist file System/Library/CoreServices/systemversion.plist.

iOS Version

This plist clearly shows the iPhone is on iOS version 13.6 and is the correct answer to the challenge.

Application Analysis - 20 points

What is Ruth’s user_id on TikTok? (answer is the string of numbers, not the user_name).

The user_id can be found on the in the TikTok databases, but it can also be parsed with AppGenie as well. The database that TikTok contacts are found in is located in private/var/mobile/Containers/Data/Application/314C0D76-AD79-43D9-93F6-5369A847BEE5/Documents/AwemeIM.db, in the AwemeContactsV3 table. Or, AppGenie can parse it us.

TikTok user_id

No matter which method is used, Ruth’s user_id is returned as 6854514343108871173 and is the solution.

Password Recovery - 20 points

What is the password that can be used to access the link recovered from the locked notes? (answer is caSE SenSITive).

This question actually took a while to solve. It needs to be solved after solving the Database Analysis question and getting the DropBox link. Ultimately, there was no real system used to find the password. A password was found while going through other conversations in an attempt to solve another challenge. The password was found in a TikTok chat that began on 8/13/2020.

Dropbox password

Stumbling across the passowrd Dr3@mT3@m11, we tried using it to unlock the link and it surprisingly worked! And is the solution to this challenge. The unlocked DropBox has one file stored - Ruth.z7.

Dropbox

Decompressing the file reveals an iPhone image of Ruth’s phone before it was reset! This is used to answer several of the challenges.

Device Status - 20 points

When was Ruth’s iPhone last wiped? Provide the date in the following format MM-DD-YYYY)

The date of the last wipe can be found using the file /private/var/root/.obliterated. The timestamp on that file is the last time the device was restored, reset, or erased.

Obliterated

The timestamps on the file are listed as 7/27/2020, and that is the correct solution to this challenge.

PList Analysis - 20 points

When was the WiFi for “Birchrunville_cafe-Guest” first connected (added) to Ruth’s iPhone? The answer must be provide in localtime for the device. (UTC WILL NOT BE ACCEPTED). Answer must be in the following format MM-DD-YYYY HH:MM:SS (i.e. 12-18-2019 23:52:23)

This question and the next question need to be answered using the second image of Ruth’s phone obtained in the Password Recovery question. The answer to this question can be found by going to the Wireless Networks tab and sorting by the SSIDs.

WiFi

The time it was first connected to is the timestamp shown. In the format required by the question, the solution is 07-09-2020.

Application Usage - 20 points

How much time did Ruth spend on TikTok on 07-25-2020? (Answer must be in this format 00:05:27)

This question can be easily solved by looking at the timeline. First, filter by the data in question, 7/25/2020. Then search for the TikTok identifier com.zhiliaoapp.musically. This returns 7 rows, 2 of which are application usage logs.

Application usage

Subtracting the times returned, 5:53:47 - 5:51:23 = 00:02:24. The correct solution is 00:02:24.

Application Usage - 20 points

How did Ruth listen to the podcast titled “Episode 4: The Importance of Test Data” on this device? (Answer must be just the application name i.e. spotify)

The first place to check is the default Podcasts app. Information on Podcasts is not found in the Podcast app or it’s databases, it is actually found in /private/var/mobile/Media/iTunes_Control/iTunes/MediaLibrary.sqlitedb, the default media library database. After searching the different tables for the keywords “Episode 4”, it can finally be found in the item_extra table.

Podcast in database

This confirms the default iOS Podcast app was used. The question has an example application name in all lower case. So entering podcast is the correct answer.

Application Usage - 20 points

Ruth listened to a podcast titled “Episode 4: The Importance of Test Data” on this device. Once you determine how she listened to it, what is the item_pid for this podcast?

Easy enough! This answer is found in the exact same place we used to answer the last question.

Podcast in database

The item_pid is the first column from the left. 239332200929536034 is the solution to this challenge.

Database Analysis - 50 points

What is the link that was found in a locked note? (Hint: it is a good idea to use this link as it’s a hidden flag and it’s safe!)

The link can be found after unlcoking the locked note, which is described in the Application Analysis_Notes question.

Unlocked notes

The link from the note and solution to the challenge is https://bit.ly/3arhLSK. The shortened link takes us to a password protected DropBox link.

Financial Information - 50 points

What is the routing number used by Ruth to make and receive payments for potentially illegal transactions?

Gerbinator again came in clutch on this question. After too long searching anywhere we could think on Ruth’s phone, Gerbinator had the idea to check the other images provided. They came across the same SplashScreen image from Juan’s Financial Situation question. That image had a routing number in the image.

CashApp Splashscreen

Attempting that routing number, especially since it’s the only one we could find that it could possibly be, it turns out that is the correct answer - 041215663!!

Application Analysis_Notes - 100 points

What is the password to unlock the Notes on Ruth’s device? (case sensitive - as all passwords should be!) You won`t find the answer, but can draw clues to it. Google could help once you find the correct hint.

A bit of research led to the discovery of this Perl script that can be used to extract the hash of any locked notes file from the NoteStore.sqlite. The hash can than be used in a dictionary + mask attack using Hashcat. Hashcat supports iOS note hash cracking with the -m 16200 mode. All of the passwords we have seen up to this point have used l33tsp3ak. Using a l33tsp3ak mask in combination with the Rockyou wordlist reveals that the password is w3ndy$. Reloading Ruth’s image and inputting that as the locked note password reveals the contents of the note and is the answer to this challenge.

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