Overcoming Impediments to Cell Phone Forensics

Cell phones are an emerging but rapidly growing area of computer forensics. They can hold a wealth of information about the user, such as contacts, messages, photos, videos, documents, and more. However, recovering digital evidence from cell phones is not as straightforward as from personal computers. There are many factors that impede cell phone forensics, such as the diversity of device models, operating systems, storage structures, and protocols. In this blog post, I will discuss some of the challenges and solutions for overcoming impediments to cell phone forensics.

Challenge 1: Limited coverage of available phone models by forensic tools

One of the main challenges in cell phone forensics is the limited coverage of available phone models by forensic tools. According to a report by NIST, there were over 10,000 different cell phone models in the market in 20081. However, most forensic tools only support a fraction of them, and often lag behind the latest releases. This means that forensic examiners may encounter devices that are not supported by any existing tool, or that require manual intervention to extract data.

One possible solution to this challenge is to develop more generic and adaptable forensic tools that can work with a wider range of devices. For example, some tools use a technique called “chip-off”, which involves physically removing the flash memory chip from the device and reading its contents using a specialized reader. This method can bypass the device’s security mechanisms and access raw data, but it also requires advanced skills and equipment, and may damage the device or the evidence. Another possible solution is to leverage open source software and community efforts to create and share forensic tools and scripts for various devices. For example, some tools use the Android Debug Bridge (ADB) protocol, which is a standard interface for communicating with Android devices. This protocol can be used to access data from supported devices, or to run custom commands and scripts to extract data from unsupported devices.

Challenge 2: Inadequate means for validating the correct functioning of forensic tools

Another challenge in cell phone forensics is the inadequate means for validating the correct functioning of forensic tools. Unlike personal computers, cell phones do not have a standard file system or data format, and often use proprietary or encrypted data structures. This makes it difficult to verify the accuracy and completeness of the data extracted by forensic tools. Moreover, forensic tools may have bugs or errors that affect the reliability of the results, or may introduce artifacts or modifications that alter the original data.

One possible solution to this challenge is to establish a rigorous testing and validation process for forensic tools, using standardized test cases and datasets. For example, NIST has developed a project called Computer Forensic Tool Testing (CFTT), which aims to provide objective and repeatable testing of forensic tools. The project has published several reports and test results for various types of forensic tools, including cell phone forensic tools. Another possible solution is to use multiple forensic tools and compare the results, or to use manual verification methods, such as examining the device’s screen or comparing the device’s data with other sources of evidence.

Conclusion

Cell phone forensics is a fast-growing and dynamic field that offers many opportunities and challenges for forensic examiners. As cell phones become more powerful and complex, forensic tools need to keep up with the latest developments and innovations. Moreover, forensic tools need to be tested and validated to ensure their correctness and reliability. By overcoming the impediments to cell phone forensics, forensic examiners can recover more valuable and relevant information from cell phones, and use it to support investigations and prosecutions.