chetan-mining_digital_evidence_in_microsoft_windows

Mining Digital Evidence in Microsoft Windows

– Answering Who, When, Why and How?

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Agenda

CSI Computer Crime and Security Survey, 2007

What is Computer Forensics?

Laws of computer Forensics

10 Forensics avenues in Windows XP

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A Quick CSI-FBI 2007 Survey Summary

The average annual loss in 2007 - $350,424 Average annual loss in the previous year - $168,000.

Not since the 2004 report have average losses been this high!46% of the overall respondents said that they had suffered a security incident.Almost one-fifth (18 percent) of those respondents who suffered one or more kinds of security incident further said they’d suffered a “targeted attack”Financial fraud - the source of the greatest financial losses.

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CSI Computer Crime and Security Survey

Insider abuse of network access or e-mail - the most prevalent security problem – 59% percent of respondentsVirus incidents – 52% percent of respondentsDollar Amount Losses

Financial Fraud - $21,124,750Virus (Worms / Spyware) - $8,391,800Theft of Confidential Data - $5,685,000Insider abuse of resources - $2,889,700

Total losses for 2007 - $66,930,950

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CSI Computer Crime and Security Survey

How many Incidents in the past twelve months?

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Computer Forensics – the laws

First Law of Computer Forensics

There is evidence of every action.

Harlan Carvey’s Corollary :

Once you understand what actions or conditions create or modify an artifact, then the absence of that artifact is itself an artifact.

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Tip of the “Digital” Iceberg

Data as seen by a casual observer using common tools (Explorer Window, cmd shell, web browser etc. )

Data as seen by Forensic Investigators using his sophisticated toolkit. May include deleted data, hidden data, unauthorized information and records of illegal activity!

Mining Windows XP

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Windows XP – Market Share

92.69% of the people surfing the Web use Windows on PCs

Windows XP’s share - 79.32%Windows Vista – 7.38%

Source: http://marketshare.hitslink.com

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NTFS attributes Registry Files PreFetch Files (.pf) Spooler Files Recycle Bin info2 records Thumbs.db Event Logs (.evt) Internet History Files (.dat) Shortcut files (.lnk) Restore Point Forensics

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NTFS attributes Registry Files PreFetch Files (.pf) Spooler Files Recycle Bin info2 records Thumbs.db Event Logs (.evt) Internet History Files (.dat) Shortcut files (.lnk) Restore Point Forensics

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Mining NTFS Attributes

MFT entry

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Mining $logfile

$Logfile entry in the MFT contains the log of all file system transactionsThe deletion of a file leaves several entries in $LogfileIt is not unusual to find files that are no longer on the diskAlso shows that the file was used by the systemEncase $logfile parser Enscript

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Mining NTFS timestamps

NTFS has four timestamps:Creation timeLast accessed timeLast written timeLast Modification time

Windows 64-Bit Time StampIt is an 8-byte string (64 bits), its most significant value is 01h, which is located at the far right of the string as it is stored in little endian.

The FN and SIA attributes

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NTFS attributes Registry Files PreFetch Files (.pf) Print Spooler Files Recycle Bin info2 records Thumbs.db Event Logs (.evt) Internet History Files (.dat) Shortcut files (.lnk) System Restore Points

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Windows Registry

Registry files are essentially databases containing information and settings for

HardwareSoftwareUsersPreferences

A registry hive is a group of keys, subkeys, and values in the registry that has a set of supporting files containing backups of its data. In Windows 98, the registry files are named User.dat and System.dat. In Windows Millennium Edition, the registry files are named Classes.dat, User.dat, and System.dat. In Win XP, the registry files are available in C:\windows\system32\config folder

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Mining Windows Registry

Multiple forensic avenues in the registry!System and User-specific settingsUserAssistMuiCacheMRU ListsProgramsCacheStreamMRUShellbagsUsbstorIE passwordsand many more!

Demo

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NTFS attributes Registry Files Prefetch Files (.pf) Spooler Files Recycle Bin info2 records Thumbs.db Event Logs (.evt) Internet History Files (.dat) Shortcut files (.lnk) System Restore Points

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The Prefetch feature

Microsoft created a Prefetch cache to improve boot and application launch time.

By caching commonly used applications the OS can determine to apportion system resources in anticipation that the user will access the application.

When an application is launched the system updates an entry in the path C:/Windows/Prefetch with the name of the application and a file extension (.pf).

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The Prefetch feature

The file contains among other items the last time that the file was modified as a 64bit HEX value time, and increments an integer on how many times the application has been run. Analyze Prefetch –Mount Image Pro (MIP) + read-only image + WFA.exeDemo

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Mining Prefetch – wfa.exe

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NTFS attributes Registry Files PreFetch Files (.pf) Print Spooler Files Recycle Bin info2 records Thumbs.db Event Logs (.evt) Internet History Files (.dat) Shortcut files (.lnk) System Restore points

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Print Spooler Files

On Windows XP, systems you would find these two files in the C:\Windows\System32\spool\Printers folder.

.SPL - The print job’s spooled data is contained in a spool file..SHD - The shadow file contains the job settings

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PA Spool Viewer – view .shd files

Splview.exe - available at http://undocprint.printassociates.com

This tool allows you to view the metadata of the print job!

http://undocprint.printassociates.com/



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EMF Spool viewer – view .spl files

EMF Spool Viewer - available at http://www.codeproject.com/dotnet/EMFSpoolViewer/EMFSpoolViewer.zip This tool allows you to view the actual spooled pages!

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Mining the Recycle bin

The INFO2 file contains records that correspond to each deleted file in the Recycle Bin;

each record contains the record number, the drive designator, the timestamp of when the file was moved to the Recycle Bin, the file size, file’s original name and full path, in both ASCII and Unicode.

Files sent to the Recycle Bin are maintained according to a specific naming convention

D<original drive letter of file><#>.<original extension>

Demo

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Mining Thumbs.db

Thumbs.db contains cached thumbnails of the images in a folder.OLE embedded data present in the Thumbs.db fileIn many cases, the images may have been deleted from the directory but they may still be available in the thumbs.db cache!Tools:

EncaseWindows File AnalyzerAccessdata FTK

Demo

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NTFS attributes Registry Files PreFetch Files (.pf) Print Spooler Files Recycle Bin info2 records Thumbs.db Event Logs (.evt) Internet History File Shortcut files (.lnk) System Restore Points

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Event Logs

Windows event logs provide crucial insight into the happenings in the systemUsing event logs in conjunction with other forensic avenue such a registry data (Userassist, Muicache, MRU Lists etc.) can help reconstructing the past events on the system. Three types of event logs:

ApplicationSystemSecurity

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Mining event logs…

What the logs can tell u:Unsuccessful logon attempts Successful Privilege escalation attemptsSystem time was changedLogon time restriction violation Logon/logoff timesSuccessful/unsuccessful object access

Default Windows security settings is to log nothing at all!Unfortunately, event logs only record the Netbios name and not the IP address!Demo

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NTFS attributes Registry Files PreFetch Files (.pf) Print Spooler Files Recycle Bin info2 records Thumbs.db Event Logs (.evt) Internet History Files Shortcut files (.lnk) System Restore Points

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Tracing Internet Activity

Internet Browsers leave detailed history on Hard drive which can show all sites visited and all graphics viewed.An individual's web browsing activity often provides investigative leads during most investigations.We can reconstruct an individual’s web browsing activity using sophisticated tools such as Encase, NetAnalysis and WebHistorianThe predominant two web browsers encountered during computer related investigations are

Microsoft's Internet Explorer (IE) and Firefox/Mozilla/Netscape family

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Mining Internet Explorer

IE maintains rich logging of a user’s browsing activities which allow for creating a web profile of the suspect. IE has three separate logging facilities that can be used to reconstruct the suspect’s web browsing activities.

History of visited URLsCookiesTemporary Internet Files

In many cases, the web profiling has lead to successful conviction of pedophiles!

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Mining Mozilla Firefox

Mozilla Firefox stores the Internet activity in the following folder:C:\Documents and Settings\<user name>\Application Data \Mozilla\Firefox\Profiles\<random text>\Cache

There are three types of files in this directory: A Cache Map File Three Cache Block Files Separate Cache Data Files

Demo

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Mining shortcut files

Link files refer to or link to target files which can be applications, directories, documents, or data files.The data contained inside a link file describes the various attributes of the target file.A link file contains:

the complete path to the target file the volume label and volume serial number on which the target file or folder exists - this can be useful for connecting a file to a unique volume!the file’s size in bytes the MAC time stamps of the target file!!!

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Mining shortcut files…

Media type (fixed/removable)Working directoryMAC addressRemote share name

May be found in unallocated clusters and swap spaceMay indicate that data was copied to a removable media!Encase link parser EnScriptWindows File AnalyzerDemo

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The restore point feature

Rp.log is the restore point log file is located within the restore point (RPxx) directory.

This restore point log contains a value indicating the type of the restore point, a descriptive name for the restore point creation event (i.e, application or device driver installation, application uninstall etc. )the 64-bit FILETIME object indicating when the restore point was created

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The restore point feature

Change.log.x files Record changes to key application filesWhen a change is detected, the original filename is entered into the change.log file along with a sequence number and other necessary information,such as the type of change that occurred (file deletion, change of file attributes, or change of content).Sometimes the entire file may be preserved (Axxxxxx.ext format)!Each change.log.x file consists of a number of change log records

Ref: Windows Forensic Analysis by Harlan Carvey

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Mining restore points

What restore points can tell:

Installation or removal of an applicationChanges to the system timeRemnants of deleted/uninstalled applicationsRemnants of deleted filesEvidence of files being accessed in the past

Demo

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Queries are welcome!

chetan-mining_digital_evidence_in_microsoft_windows

Economy & Finance

pf spooler files

dat shortcut files

evt internet history

mining windows xp

set of supporting files

pf print spooler files

microsoft windows

forensics avenues