Understand what “Live Acquisition” is and when it is appropriate Understand the concept of “Order of Volatility” Understand live acquisition issues and limitations Be able to perform live acquisition using various tools and techniques 2
Previously, our focus has been on “dead” or “cold” forensics Capture and analysis of “static state” data stored on digital storage media, where all captured data is a “snapshot” of the entire media at a single point in time where the data is write protected and/or not changing during acquisition.
Live Acquisition involves the capture of data from a system that is running when you encounter it.
Capture before you shut it down, or in lieu of shutting it down.
Capture of ever-changing data stored on media or memory, including: Data stored on internal or external disks Data active in memory (RAM) Running processes, open network connections/ports, remote and local logged on users, ARP cache, and many other items.
Write protection of “running” disks not possible with current tools or technology 3
Loss of data during shutdown Pagefile set in registry to wipe at shutdown “Evidence eliminator” apps that remove data at shutdown Data not stored on disk (RAM contents, open ports, running processes, logged on users, etc.) Encryption Full Disk Encryption or open encrypted volumes Cached passwords/passphrases in RAM???
Volume of Data Too much to image everything?
If you don’t need it all… 4
Incident Response Volatile data, lost if you turn off the computer Suspect processes running only in RAM, not on disk.
Court or client imposed business interruption restrictions Kiosk/Internet Café Maybe no hard drive, booted by CD and everything is in RAM Data in the “Cloud” Discuss with your attorney if not a consent or client/consultant situation!
The Order of Volatility is a concept, not a formal list or specific order you must follow. All data is volatile.
Certain types of data are more persistent (longer-lasting) than others.
Registers, caches, etc.: nanoseconds RAM contents: nanoseconds Network state (active/listening connections): miliseconds Running processes: seconds Disk contents: minutes Backup disks/storage: years Every process you do to capture or view a piece of data, modifies other pieces of system data in the process.
Capturing RAM will take time to complete, and during that time, other useful information such as running processes, open files, network connections, will likely have changed or disappeared.
While overall memory is continuously changing, on a new system with a large amount of RAM, many memory pages may linger for considerable time without being overwritten.
There is no absolute step-by-step order in which you should capture volatile data…every case is different!
The examiner must be aware of the overall context of the investigation in order to make informed decisions on the order of evidence acquisition, based on what information is most important to them in this case.
The computer is running, everything you do modifies the system in some way.
The more you do, the more you modify. Only do what is necessary.
Your process should be reproducible, but the results of your capture will likely not be reproducible. The state of the system and live data will never again be exactly the same as it was when you captured it.
Pre-acquisition hash values of disks or partitions that are changing during acquisition will not verify against a hash of the captured data and are therefore not appropriate.
Pre-acquisition hashes of individual files or any other data that is not changing during the live acquisition process will verify against hashes of the acquired data, and are therefore appropriate to utilize.
Post-acquisition hashes are still appropriate to later authenticate that copies of your “original” captured data is identical.
Not all tools are created equal! Many tools were not designed for “live response” but are often used as such and have a much larger system footprint than you might like. Typically, the smaller the memory footprint, the better.
Can you really testify about what your live processes touched?
Do all tools/methods touch the same memory addresses?
What do they overwrite when you run them?
How do you know? Did you perform comparison test of your tools using memory reading/debugging tools?
Imaging a running hard disk?
You will get a “smear” image!
If you need to “boot” a restored version of an image, a “smear” may not boot!
Be aware of your capture tool’s shortcomings.
Does it capture NTFS or other file system unique attributes?
What happens if the image/archive get’s corrupted (bad sector), is it recoverable?
Does it preserve all file system dates/times? Or modify them in the acquisition process?
How is the compression/speed when acquiring? How long will this take?
What tool(s) will you use to analyze the data you capture?
RAM analysis tools are new and developing, but far from refined.
Much data is not in plain ASCII text format. Will you be able to search or decipher the captured live data?
Most everything (process list, open ports, etc.) will be included in a RAM image, but parsing out this info in a usable format may be difficult or impossible with current tools.
Capture of items like process lists, open ports, etc. using Sysinternals tools (or other) may be a better option.
Local Data Collection Physical access to subject computer Portable tools run locally Forensic disk imaging Archiving, backup, logical copying Volatile data capturing Data captured onto locally attached disk (USB, IEEE1394, etc.) Network Data Collection Pre-installed on network computers On-the-fly options (push remote agent) Run tool locally & push result to other machine on the network via netcat or similar External network scan of subject computer 14
Many tools require “Administrative” or elevated permissions to run and access various “protected” system information.
Console may be locked.
Remote network collection of data may be possible.
Limited options in an adversarial situation without Administrator cooperation.
Run from a disk you introduce to the running system (i.e. CD/DVD/USB/IEEE1394/SATA/etc.) When possible, always use your own trusted tools and/or binaries. Do not rely on the soundness of built-in OS tools or those pre-installed on a subject computer, especially in potentially compromised systems (i.e. incident response).
Example: command.com edited with a HEX editor to “swap” DIR and DEL commands.
Some of your standard tools will run on a variety of OSs For example, FTK Imager Lite runs on most “live” Windows versions.
Many OS component tools (i.e. netstat, nbtstat, ipconfig, etc.) are OS version dependant and you must have trusted versions of any such tools for all the OS versions you will encounter. 19
Automated tool kits Windows Forensics Toolchest (WFT) Incident Response Collection Report (IRCR) First Responders Evidence Disk (FRED) Computer Online Forensic Evidence Extractor (COFEE)
Sysinternals Suite http://technet.microsoft.com/en-us/sysinternals/default.aspx
Many Sysinternals tools are used in the above “automated” tool kits.
Standard OS commands (your own binaries) X-Ways Capture RAM capture: WinEn, dd, Nigilant32, FTK Imager, WinHex/XWF, and many more…
Pre-installed or ability to “push” remote agent to subject machine with Admin permissions.
Most remote agents can be installed/pushed in normal or stealth modes to avoid detection.
Tools: OnlineDFS EnCase Enterprise (or FIM) AccessData Enterprise ProDiscover-IR F-Response Several others… 26
Results without Admin credentials Results with Admin credentials 28
Results affected by Firewall or other IDS/IPS protection.
Results affected by user credentials utilized to perform scan.
Only scans and reports on the items you specify in your scanning tool’s profile.
Exhaustive scanning profiles can take significant time.
Physical seizure without shutdown???
Take it back to your office to work on it.
Keep system console from locking or hibernating with “Mouse Jiggler” http://www.youtube.com/watch?v=erq 4TO_a3z8 http://www.youtube.com/watch?v= G8sEYCOv-o&feature=related 31
Use the discussion board, as usual…