Difference between pages "Vista thumbcache" and "Template:Incident response"

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(Overview)
 
 
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== Overview ==
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[[Category:Incident Response]][[:Category:Incident Response|Incident Response]]
 
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[[Windows]] Vista stores [[Thumbnails | thumbnails]] in the following directory: ''\Users\\AppData\Local\Microsoft\Windows\Explorer''
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This directory contains following files:
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* thumbcache_idx.db
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* thumbcache_32.db, thumbcache_96.db, thumbcache_256.db, and thumbcache_1024.db
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* thumbcache_sr.db
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Thumbnails are stored in ''thumbcache_NN.db'' files in different formats (e.g. [[BMP]]) and can be extracted using [[File Carving | file carving]]. There are several tools that can work with Vista Thumbcache: [http://www.dmthumbs.com/ dmThumbs], [http://www.janusware.com/fetch.php?page=412,2 Thumbs.db Viewer], [http://www.simplecarver.com/tool.php?toolname=WinThumbs%20Extractor WinThumbs] and [[FTK]]. Unfortunately, there is no information in the thumbcache that can easily link thumbnails with original files in all cases. One of the ways to link thumbnails with original files is to use Windows Indexer (Windows.edb) database.
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== Thumbcache Format ==
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''Thumbcache format is described [http://www.noxa.org/blog/?p=5 here].''
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In general, every thumbnail in cache is associated with two 64-bit variables. First variable (sometimes called ''Unique ID'', ''Secret'', ''File ID'') associates data in file ''thumbcache_idx.db'' with thumbnail data in ''thumbcache_NN.db'' files; the purpose of this variable is unclear. Another variable is ''Thumbnail Cache ID'' (sometimes called ''Thumbnail filename'' (in [[FTK]]), ''File Ref'') is used to link thumbnails with original files. Actually, ''Thumbnail Cache ID'' is represented as Unicode string of HEX encoding.
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== Thumbnail Creation Process ==
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[[Windows]] Vista creates thumbnails for files on different media types, including:
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* Removable devices
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* Network drives
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* Encrypted containers (e.g. [[PGP]] Desktop, [[TrueCrypt]], [[BestCrypt]])
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[[Windows]] Vista doesn't create thumbnails for files encrypted using [[EFS]] unless thumbcache directory is encrypted too; [[Windows]] Vista doesn't delete thumbnails for files after they were encrypted using [[EFS]].
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Some programs may generate thumbnails for some file types which are displayed in Windows Explorer, but not stored in the thumbcache (e.g. Ascon Kompas).
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== Linking thumbnails with original files ==
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=== Using Windows Indexer ===
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[[Image:WindowsPowerShellThumbnails.jpg|thumb|right|Windows PowerShell displays association between files and ThumbnailCacheIDs]]
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One way to link thumbnails with original files is to use Windows Indexer database, which stores association between '''indexed''' files and ''ThumbnailCacheIDs'' with some metadata.
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==== Using Windows PowerShell ====
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Windows PowerShell provides easy way to access this database using SQL queries. Note that most forensic tools (like [[FTK]]) display ''ThumbnailCacheID'' ([[FTK]] calls it ''Thumbnail filename'') in hexademical, but Windows PowerShell returns the result in decimal.
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==== Using HEX editor ====
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You can also search for ''ThumbnailCacheID'' value in ''Windows.edb'' file using your favorite HEX editor.
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== External Links ==
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* [http://www.whereisyourdata.co.uk/data/modules/wfdownloads/visit.php?cid=4&lid=9 Forensic Implications of Windows Vista, Barrie Stewart, 2007]
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=== Non-English ===
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* [http://itdefence.ru/content/articles/Thumbnails.Suhanov/ Использование централизованных баз данных эскизов для исследования графических файлов на зашифрованных разделах], ITDefence, 2009 ([http://www.securitylab.ru/analytics/370474.php extended version])
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Latest revision as of 14:25, 12 January 2014

Incident Response