Criminals sometimes damage their mobile phones in an attempt to destroy evidence. They might smash, shoot, submerge or cook their phones, but forensics experts can often retrieve the evidence anyway. Now, researchers at the National Institute of Standards and Technology (NIST) have tested how well these forensic methods work.
A damaged phone might not power on, and the data port might not work, so experts use hardware and software tools to directly access the phone’s memory chips. These include hacking tools, albeit ones that may be lawfully used as part of a criminal investigation. Because these methods produce data that might be presented as evidence in court, it’s important to know if they can be trusted.
“Our goal was to test the validity of these methods,” said Rick Ayers, the NIST digital forensics expert who led the study. “Do they reliably produce accurate results?”
The results of the NIST study will also help labs choose the right tools for the job. Some methods work better than others, depending on the type of phone, the type of data and the extent of the damage.
The study addresses methods that work with Android phones. Also, the study covered only methods for accessing data, not decrypting it. However, they can still be useful with encrypted phones because investigators often manage to get the passcode during their investigation.
To conduct the study, NIST researchers loaded data onto 10 popular models of phones. They then extracted the data or had outside experts extract the data for them. The question was: Would the extracted data exactly match the original data, without any changes?