Microsoft Windows uses a paging file, called pagefile.sys, to store frames of memory that do not current fit into physical memory. Although Windows supports up to 16 paging files, in practice normally only one is used. This file, stored in %SystemDrive%\pagefile.sys is a hidden system file. Because the operating system keeps this file open during normal operation, it can never be read or accessed by a user. It is possible to read this file by parsing the raw file system (e.g. using The Sleuth Kit).
Data is stored in the paging file when Windows determines that it needs more space in physical memory. Because storage locations in the paging file are not necessarily sequential, it is unlikely to find consecutive pages there. Although it is possible to find data in chunks smaller than or equal to 4KB, its the largest an examiner can hope for.
Sadly, the most productive method to date for analyzing paging files is searching for strings. It is possible to carve out files, but as noted the examiner is unlikely to find anything larger than 4KB.
- Nicholas Maclean published his thesis on Windows memory analysis and discussed the paging file. Unfortunately the document does not appear to be online anymore.
- Using Every Part of the Buffalo in Windows Memory Analysis - A paper discussing the different states of memory including where to find data in the paging file
- Microsoft Windows Internals - An excellent guide to the inner workings of Microsoft Windows