BFU (Before First Unlock)

Refers to a device state, the device has been turned off and no passcode/password has been entered by the user. This state leaves the file system encrypted, software such as XRY Pro can still successfully brute force and decrypt the file system for an extraction dependent on device make and model.

 

BFU, or Before First Unlock, is a term used in mobile forensics to describe the state of a mobile device before it has been unlocked for the first time after being powered on. This concept is particularly relevant to iOS devices and has significant implications for data acquisition and forensic analysis.

BFU vs. AFU

BFU is often discussed in contrast to AFU (After First Unlock), which refers to the state of a device after it has been unlocked. The distinction between BFU and AFU is crucial because the amount and types of data accessible in each state can differ significantly.

Implications of BFU in iOS Forensics

In a BFU state, an iOS device has limited data available for extraction. This typically includes system files, databases, and some application data that are not protected by encryption tied to the user’s passcode. However, much of the user-generated content, such as messages, photos, and email, remains inaccessible until the device is unlocked (i.e., enters an AFU state).

For forensic investigators, the BFU state presents both challenges and opportunities:

Challenges: Acquiring data from a device in a BFU state may result in an incomplete dataset, as many files and application data remain encrypted and inaccessible. This can limit the amount of evidence available for analysis.

Opportunities: The BFU state can be advantageous in certain situations, such as when a device is locked with an unknown passcode. In this case, techniques like logical acquisition can still recover some data, providing investigators with a starting point for their analysis.

FAQs

What does BFU mean in mobile forensics? BFU stands for “Before First Unlock” and refers to the state of a mobile device before it has been unlocked for the first time after being powered on. This term is commonly used in the context of iOS forensics.

What data is accessible in a BFU state on an iOS device? In a BFU state, an iOS device typically allows access to system files, databases, and some application data that are not protected by encryption tied to the user’s passcode. However, much of the user-generated content, such as messages, photos, and emails, remains inaccessible until the device is unlocked.