Mobile devices are transforming into vast repositories of digital evidence. Each tap, swipe, and notification leaves a trail that can help reconstruct events, verify alibis, or uncover hidden connections in major cases.
Like PCs, smartphones use various operating systems that impact forensic analysis. For example, iOS offers data protection that locks files and renders them inaccessible without the correct passcode. Read on to learn how Mobile Forensics is changing the name of the game.
Evidence Collection
As a form of digital forensics, mobile device forensics examines data on digital devices, including smartphones and tablets. It involves analyzing the evidence in a legally acceptable manner, ensuring that it can be used as admissible in court. It focuses on gathering, extracting, preserving, and reporting on electronic evidence for criminal investigations, corporate security, and electronic discovery.
As more people own and use mobile devices, the amount of available evidence grows significantly. For example, mobile phones store a huge amount of information about a user’s location and the dates and times of phone calls, text messages, and other activity. Investigators can also retrieve data from cloud services such as email and calendar accounts, social media sites, GPS applications, and more.
In addition, mobile devices can be connected to a variety of other systems that may contain relevant evidence, such as car navigation systems and satellite radios. Forensic examiners must understand how to access this interconnected ecosystem and determine the scope of the investigation.
One of the biggest challenges in collecting mobile device evidence is that the data is constantly changing. As users install new apps, the operating system updates, and even delete old data, it becomes difficult to find the right evidence in time. The process also requires a high level of knowledge and expertise in a wide range of areas, including mobile technology, hardware, and software.
The first step in conducting a mobile forensics investigation is to secure and document the device. Once the device has been seized, forensic examiners can begin the process of extracting data through file system acquisition. This involves making a sector-to-sector copy of the device’s files using a specialized tool or software imaging platform that maintains the integrity of the original file system and allows for the recovery of deleted evidence.
Once the forensic process is complete, investigators can examine the results and make a report on the findings. These reports are often used in criminal cases, but can also be useful for civil litigation and internal investigations of companies or organizations. They also help to establish the chain of custody and prove that the process was carried out properly and in accordance with the law.
Data Extraction
A mobile device’s data is continuously modified, so it can be difficult to know what’s worth preserving for future analysis. For this reason, it’s important to use mobile forensic tools that allow you to acquire (or forensically copy) only the data you need from your evidence.
This is known as targeted extraction, and it’s the fastest method for obtaining granular data—such as messaging, pictures, videos, contacts, Internet, and social media information related to a particular application or date of interest. Targeted extraction also avoids the use of external drives or cloud storage, so it keeps forensic integrity intact.
In addition to targeted extraction, mobile forensics can be used to examine local and cloud backups to obtain evidence that isn’t readily accessible on the actual device itself. This is especially useful when a device has been factory reset or lost. For example, call detail records and cell site dumps (tower dumps) are available from wireless carriers to provide evidence of where a device was when a specific event occurred.
Mobile forensics is a rapidly evolving field, and new technologies require new forensic tools. But even with these advances, a mobile forensics expert must follow established protocols that ensure the reliability of digital evidence and the chain of custody. These protocols apply to all aspects of the forensics process—from initial extraction to preparing final reports.
The forensics process begins with a thorough documentation of the device’s IMEI or MEID number and SIM card, bootloader, lock screen state, and physical condition. This information is critical to establishing a proper chain of custody and providing context for subsequent analyses.
Using physical or logical extraction methods, the forensic examiner makes a sector-to-sector copy of the data stored on the device’s memory. This can include everything found in a traditional extraction, such as SMS/iMessage, photos, and contacts, but also hidden files like system logs, crash logs, location caches, and app-specific directories stored in private folders.
This step is vital for high-stakes investigations involving corporate espionage or insider threats. By examining the file system structure of a device, forensic experts can recover deleted files and identify patterns that might indicate suspicious activity. This includes analyzing metadata, correlating timestamps across different applications, and investigating active SQLite databases, plist files, and system logs.
Analysis
Forensic analysis of mobile devices involves looking through the data retrieved to find useful information for the investigation. The goal is to get proof that will support criminal and civil cases in areas such as theft, fraud, or acts of violence. Depending on the case, it may also be relevant to business-related issues like contract breaches or harassment claims. The scope of mobile forensics is wide-ranging and requires experts to be proficient with multiple tools and familiar with the legal issues surrounding digital technology.
For example, the Android ecosystem is notoriously diverse, with device manufacturers implementing custom features and security measures on top of standard operating system components. These modifications impact hardware configurations, system applications, and the way data is stored on the device. Investigators must be able to analyze the device file structure and understand how the customizations impact evidence acquisition.
Another challenge is the growing use of sophisticated encryption technologies to protect digital evidence. Forensics experts must be able to bypass encryption protection measures and extract encrypted data for further examination. This is one reason it’s so important for forensic examiners to stay up-to-date on new and emerging forensics standards.
Mobile forensics professionals are highly trained to handle a variety of different types of files. They must be able to recognize the difference between a file that has been backed up in a cloud or synchronized with other devices, and a file that is being accessed through a mobile app.
As a field that relies heavily on digital technologies, mobile forensics is constantly evolving to keep pace with advancing technology and legal issues. A successful career in this challenging subfield requires a combination of technical proficiency, strong communication skills, and active engagement with the professional community.
Whether examining an IoT device or a typical smartphone, the investigative process is similar. Investigators must carefully document the physical condition of the device, recording IMEI/MEID and SIM details, bootloader state, lock screen status, and more. These initial steps are vital for establishing a proper chain of custody and providing context to subsequent stages of the examination. In addition, forensic examiners must be able to identify the type of evidence they are collecting from the device and the manner in which it was acquired.
Reporting
Mobile devices store a huge amount of sensitive information. Understanding how to extract, analyze, and report on this data while adhering to forensically sound practices can be invaluable for law enforcement, cybersecurity professionals, and anyone interested in privacy and security.
Forensic mobile device analysis enables investigators to retrieve, process, and report on a variety of data, including contact lists, calendar and notes, SMS and MMS messages, photos, videos, web browsing history, and more. This can be especially valuable for investigations involving suspected fraud, identity theft, stalking, or other crimes that involve personal electronic data.
The forensics process starts with a physical or virtual acquisition of the device and meticulous documentation to ensure the chain of custody. This includes capturing the IMEI/MEID and SIM number, bootloader state, lock screen status, and more. This is especially important for cases involving mobile devices with advanced encryption protocols such as iMessage, WhatsApp, and Telegram.
Next, the forensic examiner can use various extraction techniques such as logical, file system, JTAG, and chip-off acquisitions to access the data on the device. This is a complex and time-consuming process, but it is the only way to recover all available evidence.
Depending on the type of investigation, examiners may also need to parse and decode data. This can include examining SQLite WAL files, plist files, and system logs to create an activity timeline. In addition, specialized tools can help identify app data and even recover deleted files from encrypted devices.
As the technology evolves, mobile forensic examiners must keep abreast of developments to avoid errors. Quality assurance measures and technical peer review help identify potential problems before they impact case outcomes. The growing number of IoT devices and cloud-integrated platforms presents additional challenges for digital forensics.
Experts who are familiar with the current state of mobile forensics, emerging trends, and best practices are able to address these challenges effectively. Maintaining a strong foundation in forensic principles while adapting to new technology enables mobile forensics practitioners to be proactive about protecting the integrity of digital evidence and ensuring admissibility in court.