Forensics of a Windows System
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The document discusses computer forensics in the context of investigating a Windows system. It outlines the process of gathering volatile data like memory contents and network connections using tools run from a trusted CD. Non-volatile data like the filesystem is acquired by imaging the entire disk. Timeline analysis uses data from files, registry keys and logs to determine when files and events occurred. The goal is to methodically identify and preserve digital evidence while following forensic standards.
Forensics of a Windows System
- 1. Pharmaceuticals FIST Conference September/Madrid 2005 @ Forensics of a Windows system Alfredo Reino Systems Engineer Pharma Global Informatics F. Hoffmann-La Roche
- 2. Pharmaceuticals F. Hoffmann – La Roche A Global Healthcare Leader • One of the leading research-intensive healthcare groups • Core businesses are pharmaceuticals and diagnostics • A world leader in Diagnostics • The leading supplier of medicines for cancer and transplantation and a market leader in virology • Employs roughly 65,000 people in 150 countries • Has R&D agreements and strategic alliances with numerous partners, including majority ownership interests in Genentech and Chugai
- 3. Pharmaceuticals Agenda • What is forensics? • Role of forensics in incident handling • Gathering volatile data • Filesystem acquisition • Timeline analysis • Network information • Tools
- 4. Pharmaceuticals What is forensics? Computer forensics is the process of investigating data storage devices and/or data processing equipment typically a home computer, laptop, server, office workstation, or removeable media such as compact discs, to determine if the equipment has been used for illegal, unauthorized, or unusual activities. It can also include monitoring a network for the same purpose. They must do so in a fashion that adheres to the standards of evidence that is admissible in a court of law. http://en.wikipedia.org/wiki/computer_forensics
- 5. Pharmaceuticals What is forensics? • Computer forensics includes the following aspects: – identify evidence – preserve evidence – analyze evidence – present results • This has to be done following appropiate standards, especially if results need to be admitted by court of law
- 6. Pharmaceuticals Incident handling • General areas of incident handling – planning and preparation – incident detection – containment / response – recovery – analysis
- 7. Pharmaceuticals Forensics scope and environment applications os server computerized systems infrastructure systems lan / dmz external environment do you have all the relevant information?
- 8. Pharmaceuticals Gathering data • Volatile data – registers, cache contents – memory contents – network connections – running processes • Non-volatile data – content of filesystems and drives – content of removable media
- 9. Pharmaceuticals Volatile data - preparation • Create cd-rom with trusted toolset – at least include a trusted version of CMD.EXE from the same operating system – netcat or cryptcat (http://sourceforge.net/projects/cryptcat/) – system tools (ipconfig, netstat, date, time, net, arp ...) for different windows versions and service pack levels – pstools, listdlls, filemon, regmon, autoruns... (http://sysinternals.com) – hfind, fport, ntlast, ... (http://foundstone.com) – windows resource kit tools – a good sniffer (ethereal, windump, ...) – md5sum / md5deep
- 10. Pharmaceuticals Volatile data - the set up • Connect forensics workstation to same lan as suspect server • Configure netcat or cryptcat in forensics workstation to listen on a port and save received data to evidence file • Mount trusted toolset cd-rom in suspect server • Open trusted console (cmd.exe)
- 11. Pharmaceuticals Volatile data - what to get • System date and time • Running processes • Network connections • Open ports • Applications listening on open sockets • Logged on users
- 12. Pharmaceuticals Volatile data - tools • date /t & time /t – get system date and time • ipconfig /all – get tcp/ip configuration • netstat -aon – get network connections and listening ports (with associated process pid) • psinfo -shd – get computer information (hardware, software, hotfixes, versions, etc.) • pslist -t – get running processes
- 13. Pharmaceuticals Volatile data - tools • psloggedon – show logged on users and log on times • psloglist – dump event log • psservice – dump system service information • net use – list netbios/smb connections • listdlls – list all dlls loaded in system • sigcheck -u -e c:windowssystem32 – enumerate all unsigned files (.exe, .dll)
- 14. Pharmaceuticals Volatile data - tools • streams -s c: – list files with alternate data streams (ads) • logonsessions -p – lists logged on sessions and processes running on each session • strings – searches for ascii/unicode strings in suspicious files (you decide which are suspicious or not!) • arp -a – displays arp cache table • ntlast – record succesful and failed logins in system (including null sessions and remote logins)
- 15. Pharmaceuticals Volatile data - tools • autorunsc – show all kinds of autorun items • hfind c: – finds hidden files
- 16. Pharmaceuticals Volatile data - GUI tools • rootkit revealer – detects usermode or kernelmode rootkits • process explorer – useful information about running processes, loaded libraries, used resources, etc. • tcpview – displays network connections and associated applications
- 17. Pharmaceuticals Network information • Useful static data to get – IDS/IPS logs – firewall logs – radius/VPN logs – DHCP logs and leased ip information – application logs from other servers in same network if they are suspected of being entry point (ftp, www, database, ...)
- 18. Pharmaceuticals Network information • Traffic to/from live system – use of sniffer recommended – can use ethernet probe (read-only cat5 if possible!) – if server connected to hub, then plug probe into hub – if connected to switch, use a mirror port (in expensive switches) or use arp-spoofing to redirect traffic to sniffer – best sniffer: ethereal
- 19. Pharmaceuticals Filesystem acquisition • Physical acquisition – turn off machine (plug power cable) – remove harddisk – connect to forensics workstation using hardware IDE/SCSI write blocker – perform bitwise copy
- 20. Pharmaceuticals Filesystem acquisition • Network acquisition - live system – not recommended • untrusted operating system • filesystem in inconsistent state – configure forensics workstation • lots of free disk space • netcat listener (nc -l -p 9000 > disk1.dd) • after acquiring compute hash (md5sum disk1.dd > disk.md5) – acquire live filesystem • run 'dd for windows' from trusted cd-rom toolset • dd if=.PhysicalDrive0 bs=2k | nc -w 3 10.0.0.1 9000 – where 10.0.0.1 is the ip address of forensics workstation
- 21. Pharmaceuticals Filesystem acquisition • Network acquisition - non-live system – configure forensics workstation • lots of free disk space • netcat listener (nc -l -p 9000 > disk1.dd) • after acquiring compute hash (md5sum disk1.dd > disk.md5) – configure suspect system • boot suspect system (losing volatile info!) into linux livecd distro (gentoo, helix, knoppix, ...) • run dd to image disk over network with netcat – dd if=/dev/sda | nc 10.0.0.1 9000
- 22. Pharmaceuticals Filesystem analysis • Many tools for this – EnCase (commercial) – The Sleuth Kit + forensics browser – ftimes • Basic analysis tool functionality – file topography – compute hashes for files – create timeline analysis (mac data) – identify and recover deleted files – search functions – case management
- 23. Pharmaceuticals Filesystem analysis • The Sleuth Kit + forensics browser
- 25. Pharmaceuticals Timeline analysis - other sources • LastWrite information in registry keys – use 'lsreg.pl' to parse registry and extract information including lastwrite data Key -> CurrentControlSetControlWindowsShutdownTime LastWrite : Tue Aug 2 12:06:56 2005 Value : ShutdownTime;REG_BINARY;c4 96 a0 ad 5a 97 c5 01 • INFO2 files – contains information about deleted files by each user (only if it goes to recycle bin) – use 'rifiuti' to extract information – file normally at C:Recycler%SID%INFO2
- 26. Pharmaceuticals Timeline analysis - other sources • Prefetch folder – used by windows to store information about how to effectively launch executables to improve performance – XP prefetches at boot time and application launch, 2003 prefetches only at boot time (default) – .pf files in %systemroot%/prefetch folder – the .pf contains information about file paths – the mac info of the .pf file gives us information about when an application has been launched – use 'pref' or 'pref_ver' to parse this info
- 27. Pharmaceuticals Timeline analysis - other sources • Logs – event logs (application, system, security) • very useful, many tools to extract – IIS/webserver/FTP logs • useful to detect webapp exploiting (maybe as point of entry), for example unicode attacks, sql injection, ... – setupapi.log • information about installation of applications and devices – schedlgu.txt • information about scheduled tasks – antivirus logs – ...
- 28. Pharmaceuticals Timeline analysis - other sources • Recently opened documents - check this registry key (for each user!) HKCUSoftwareMicrosoftWindowsCurrentVersionExplorerRunMRU • Temp folders – examine contents for suspicious files • Web browser cache – 'pasco' tool for internet explorer forensic analysis – cache and cookies folders – browser history
- 29. Pharmaceuticals Analysis of evidence • Need to find "footprints" • Initial analysis – check for hidden or unusual files – check for unusual processes and open sockets – check for unusual application requests – check for suspicious accounts – determine patch level of system • Based on findings, we should develop a strategy for further investigation – full filesystem analysis – recovery of deleted files – password cracking – analysis of pagefile – ...
- 30. Pharmaceuticals Tools • These are the mentioned tools in this presentation • Feel free to add more to your toolkit • Script (vbscript, perl) your toolset!!
- 32. Pharmaceuticals FIST Conference @ www.fistconference.org Alfredo Reino Madrid, September 2005 Thanks for your attention.