Digital Forensics
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Module 11 CS 996. Digital Forensics. Outline of Module #11. Overview of Windows file systems Overview of ProDiscover Overview of UNIX file systems (Kulesh) ProDiscover workshop (remaining time). Reminder. InfraGard Chapter meeting on Counterintelligence Bear Stearns, 383 Madison Avenue
Digital Forensics
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Module 11 CS 996 Digital Forensics
Outline of Module #11 • Overview of Windows file systems • Overview of ProDiscover • Overview of UNIX file systems (Kulesh) • ProDiscover workshop (remaining time) Module 11
Reminder • InfraGard Chapter meeting on Counterintelligence • Bear Stearns, 383 Madison Avenue • 9-4, April 28 • RSVP: www.nym-infragard.us Module 11
Hard Drive Data Hiding Places • Low Level Format • Redundant sectors • Bad sectors • Partition • Interpartition gaps • Unallocated space • “Hidden” partitions • Boot records and partition tables • Deleted partitions Module 11
Physical Disk Geometry (CHS) • One head for each surface (H) • All tracks at r = dn form “cylinder” (C) • Each sector has 512 bytes of user data (S) • One disk surface devoted to positioning and synchronization • Not all parts of the disk are addressable by the OS • Disk capacity = C x H x S x 512 bytes Module 11
Lifecycle of Disk Drive • Blank media • Low level format • Performed at the factory • Partition • High level file system format • Operating system install • System operations Module 11
Low Level Format • Low level formatting creates sectors • Each sector holds 512 bytes + overhead bytes • Overhead provides error correction and timing recovery • Bad sectors remapped to redundant sectors by the HDD controller. Module 11
Low Level Format REDUNDANT SECTOR 512 BYTES SECTOR OVERHEAD Module 11
Partitioning PARTITION #2 PARTITION #1 MASTER BOOT RECORD INTER-PARTITION GAP VOLUME BOOT RECORD VOLUME BOOT RECORD Module 11
Partitioning Drive • Master Boot Record = Master Boot Code + Master Partition Table (MPT) • Always at sector #1 • Volume Boot Record = Volume Boot Code + Disk Parameter Block • Each partition Module 11
FAT File System • Four parts • Volume boot record • File allocation tables • Root directory • User data area • Types • FAT 12, 16, 32 bits; cluster address size • FAT1 and FAT2; first and second copy of FAT • Floppy: FAT12 Module 11
FAT12/16 Structure DOS BOOT SECTOR ROOT DIRECTORY USER DATA AREA FAT #1 FAT #2 Module 11
FAT32 Structure DOS BOOT RECORD (3) COPY OF DOS BOOT RECORD FAT #1 FAT #2 USER DATA RESERVED SECTORS RESERVED SECTORS 32 SECTORS Module 11
File Allocation Table 0 TEST 217 DIRECTORY ENTRY 217 618 339 EOF 618 339 Module 11
WinHex: Forensic Hex Editor • www.x-ways.net • Disk cloning • DOS version • Windows version (use write blocker) • Disk editor • API for scripting tasks Module 11
Navigating to FAT12 Directory • Start at boot sector #1 • Add 2 x 9 sectors • Directory at sector #20 • Offset is: 19 x 512 = 9728 bytes = 2600H Module 11
Navigating to FAT32 Allocation Table • Start at boot sector • Go to sector #33, offset of 32 x 512 bytes • 32 x 512 = 16384 = 4000H Module 11
WinHex NTFS Partition Analysis Module 11
ProDiscover Forensic Software • www.techpathways.com • Disk imaging: meets NIST Specification 3.1.6 • Works with FAT, NTFS, Sun Solaris UFS • Displays Windows ADS! • File signature analysis • Search capability • Recover deleted files and slack space • Reasonable price! Module 11
Capture Evidence Files Module 11
Image Evidence: Windows Laptop USB TO IDE ADAPTER IDE CABLE PRODISCOVER EVIDENCE DRIVE Module 11
KeyWord Search Module 11
Reporting (View=>Report) Module 11
References for Module #11 • Bill Nelson, Guide to Computer Investigations, 2004. • Warren Kruse, Computer Forensics, 2002. • Kevin Mandia, Incident Response, 2003. • EnCase Legal Journal (course web site) • www.cs.nmt.edu (cs491_02) • NTFS: Module 11