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Shadow Analyser speeds digital analysis of recovery files
Lifting the veil on hidden files
Researchers at UK computer forensics firm Disklabs have helped develop technology that will drastically speed up the forensic analysis of 'Volume Shadow Copies' (VSC) of suspect Windows computers.
The introduction of VSC technology in Windows 2003 created a huge headache for forensic investigators, who have struggled to find a viable method for extracting meaningful data from these files. The technology, since included in Windows Vista and Windows 7, allows system restores and the recovery of previous versions of files.
Current methods of analysis take a great deal of time and storage. As a result these files often get neglected in digital investigations. This has proved an even greater problem over the last couple of years as the number of digital forensic cases has soared.
"An average investigation can take 35 hours without any VSC and that there could be dozens of VSCs, each of which potentially take tens of hours each to analyse," explained Simon Steggles, a director at DiskLabs
DiskLabs has helped develop a tool called Shadow Analyser that automated the process of decompiling VSCs in order to retrieve digital evidence. Using the ‘Shadow Analyser’ tool allows computer forensics investigator to investigate the Shadow Volume Copies and "normal" data simultaneously.
The technology was developed by Lee Whitfield, a computer forensic supervisor for Disklabs, with four years' experience in digital forensics and more than 200 investigations under his belt, and US based software independent software developer Mark Mckinnon.
"This software will allow computer forensic analysts to ensure that they investigate all the data on the computer, even the files that were currently out of reach to most analysts," Mckinnon explained. "This software will make law enforcement more effective and enable them to investigate more computers in much less time.”
Whitfield explained that unlocking information in Volume Shadow Copies allowed a much fuller view of activities on a suspect computer.
"Any time a change is made to that computer that change is saved to a volume shadow file," Whitfield explained. "These files are quite complex and, until now, have been somewhat of a stumbling block for digital forensic investigators. Depending on the operating system version these shadow files are made either every day or every seven days."
"Essentially these files allow a forensic investigator to view the computer's contents from days, weeks, or even months before. This includes older versions of files as well as deleted and erased files. This means that old internet history, registry files, virtually any file that has existed on that computer in recent history can be forensically recovered."
The software is going to save time and costs while allow analysts to investigate more fully than ever before, according to DiskLabs, which plans to market to potential clients in the forensics and data recovery market.
The technology is due to be launched at an National Policing Improvement Agency conference later on Wednesday (30 June). ®