Digital Forensics Data Collections: Acquisition Methods

By Author: Sacha Ward
Total Articles: 2
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This article outlines some of the digital forensics data acquisition methods used on a regular basis to preserve metadata and ensure defensibility.

This article outlines some of the digital forensics data acquisition methods used on a regular basis to preserve metadata and ensure defensibility.

Digital forensics data acquisition methods can broadly be broken down into two categories – overt and covert. Quite simply an overt approach is one in which the subject is aware of the data collection, conversely a covert approach is one in which the subject is unaware. The method used will depend on the requirements of the investigation; in the vast majority of cases an overt approach is adopted, particularly for disclosure as part of civil litigation where a duty to preserve exists often long before collection. In general an overt approach is easier, takes less effort and is therefore the cheaper option. Although sometimes, the situation is such that a covert approach is the only option.

When it comes to covert digital forensics data acquisition we have two options: ‘dead-box’ or ‘remote’ ...
... acquisition. Dead-box involves physically taking possession of the device and acquiring data directly, then returning it before the absence is noted. Historically this has been the favoured approach, especially at a time when most users had desktop computers left in offices overnight. Nowadays the majority of users have laptops which are, more often than not, taken home at night. In addition, mobile phones are becoming ever more relevant and are rarely, if ever, parted from their owners for any great length of time.

The mobility of devices presents us with a challenge: how can we covertly acquire data when the user is never parted from their devices? The solution is to work alongside in-house IT teams to use the local IT infrastructure to our advantage. It is possible to remotely acquire data from devices with no tangible access to them. By deploying what is essentially a ‘Trojan’ to the devices (a Trojan which is secure and fully under our control), we are able to access and acquire data from user devices without their knowledge. This has proved particularly useful in investigations where the suspects were ‘home workers’ and a covert approach was required.

Whatever digital forensics data acquisition approach is adopted it is important that it is done in a forensic manner, ensuring all possible data and metadata are preserved. The process must be fully defensible should the integrity of the evidence ever be questioned.
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