@night 1803 access accessdata active directory admissibility ads aduc aim aix ajax alex levinson alissa torres amcache analysis anjp anssi answer key antiforensics apfs appcompat appcompatflags applocker april fools argparse arman gungor arsenal artifact extractor attachments attacker tools austin automating automation awards aws azure azuread back to basics backstage base16 best finds beta bias bitcoin bitlocker blackbag blackberry enterprise server blackhat blacklight blade blanche lagny book book review brute force bsides bulk extractor c2 carved carving case ccdc cd burning ceic cfp challenge champlain chat logs Christmas Christmas eve chrome cit client info cloud forensics command line computer forensics computername conference schedule consulting contest cool tools. tips copy and paste coreanalytics cortana court approved credentials cryptocurrency ctf cti summit cut and paste cyberbox Daily Blog dbir deep freeze defcon defender ata deviceclasses dfa dfir dfir automation dfir exposed dfir in 120 seconds dfir indepth dfir review dfir summit dfir wizard dfrws dfvfs dingo stole my baby directories directory dirty file system disablelastaccess discount download dropbox dvd burning e01 elastic search elcomsoft elevated email recovery email searching emdmgmt Encyclopedia Forensica enfuse eric huber es eshandler esxi evalexperience event log event logs evidence execution exfat ext3 ext4 extended mapi external drives f-response factory access mode false positive fat fde firefox for408 for498 for500 for526 for668 forenisc toolkit forensic 4cast forensic lunch forensic soundness forensic tips fraud free fsutil ftk ftk 2 full disk encryption future gcfe gcp github go bag golden ticket google gsuite guardduty gui hackthebox hal pomeranz hashlib hfs honeypot honeypots how does it work how i use it how to howto IE10 imaging incident response indepth information theft infosec pro guide intern internetusername Interview ios ip theft iphone ir itunes encrypted backups jailbreak jeddah jessica hyde joe sylve journals json jump lists kali kape kevin stokes kibana knowledgec korman labs lance mueller last access last logon lateral movement leanpub libtsk libvshadow linux linux forensics linux-3g live systems lnk files log analysis log2timeline login logs london love notes lznt1 mac mac_apt macmini magnet magnet user summit magnet virtual summit mari degrazia mathias fuchs md viewer memorial day memory forensics metaspike mft mftecmd mhn microsoft milestones mimikatz missing features mlocate mobile devices mojave mount mtp multiboot usb mus mus 2019 mus2019 nccdc netanalysis netbios netflow new book new years eve new years resolutions nominations nosql notifications ntfs ntfsdisablelastaccessupdate nuc nw3c objectid offensive forensics office office 2016 office 365 oleg skilkin osx outlook outlook web access owa packetsled paladin path specification pdf perl persistence pfic plists posix powerforensics powerpoint powershell prefetch psexec py2exe pyewf pyinstaller python pytsk rallysecurity raw images rdp re-c re-creation testing reader project recipes recon recursive hashing recycle bin redteam regipy registry registry explorer registry recon regripper remote research reverse engineering rhel rootless runas sample images san diego SANS sans dfir summit sarah edwards saturday Saturday reading sbe sccm scrap files search server 2008 server 2008 r2 server 2012 server 2019 setmace setupapi sha1 shadowkit shadows shell items shellbags shimcache silv3rhorn skull canyon skype slow down smb solution solution saturday sop speed sponsors sqlite srum ssd stage 1 stories storport sunday funday swgde syscache system t2 takeout telemetry temporary files test kitchen thanksgiving threat intel timeline times timestamps timestomp timezone tool tool testing training transaction logs triage triforce truecrypt tsk tun naung tutorial typed paths typedpaths uac unc understanding unicorn unified logs unread updates usb usb detective usbstor user assist userassist usnjrnl validation vhd video video blog videopost vlive vmug vmware volatility vote vss web2.0 webcast webinar webmail weekend reading what are you missing what did they take what don't we know What I wish I knew whitfield windows windows 10 windows 2008 windows 7 windows forensics windows server winfe winfe lite winscp wmi write head xboot xfs xways yarp yogesh zimmerman zone.identifier

Daily Blog #51: Understanding the artifacts USNJrnl

Hello Reader,
        I'm going to change tracks this week and focus on a deeper understanding of the USNJrnl and its associated artifacts to prove usage from our challenge two weeks ago. To prepare for this series I want to take a bit to explain what each of the artifacts we rely on for proof of usage were created for. When we are complete I hope you will look at your cases in a different way.

Today we are going to talk about the USNJrnl. The USN Jrnl or Update Sequence Number Journal aka the Change Journal was first introduced in Windows 2000 but didn't get enabled by default until Windows Vista (that I know of, please leave a comment if you have evidence of other default states/os's). I have seen it enabled for EFS encrypted drives on XP but I can't say if that's a default setting.The concept of the change journal was simple, many programs need to know when files are changed so they can be backed up, compressed, scanned, replicated, etc...

Prior to the change journal a developer would have to register hooks or shims into the operating system for all reads and writes to be able to be notified that a file is being created/modified/deleted and to process it. The Change Journal gave the developer a central api to monitor that covered all subscribing functions and prevented  a lot of unnecessary overhead. You can read more about the basics of the Change Journal here on wikipedia. The original announcement of it was made in September 1999 and can be found here its interesting that it took as long as it did for it to be enabled by default. You can see that it was being marketed to developers as a way to centrally monitor file system changes and improve performance.


The current change journal development documents are here and if you relying on change journal evidence in your cases you should be familiar with the use case scenario because things are not as black and white as they appear. What do I mean by that? In our testing we've found that a file left open overnight and accessed at different times will create multiple USN open/close/delete events. You cannot rely on the file open and file close times of a file to determine total time of access, it may only be showing you the times of activity against a file that was open the entire time. In addition we've found file close/file delete being used to close a file handle but not to delete the file itself.

I'm going to into more detail of how individual Change Journal operations work and get logged as we move forward so I don't want to get ahead of myself. So in summary remember that the Change Journal keeps track of file system changes for the benefit of those subscribing services. If you are unsure of a pattern of records your seeing the best thing you can do is build a virtual machine and try to recreate those actions to validate your assumptions. The Change Journal is not as simple as we all though it to be! Tomorrow I'm going to continue talking about Usage artifacts and then go into depth on the Change Journal and the rest of them. 

Post a Comment

[blogger][disqus][facebook][spotim]

Author Name

Contact Form

Name

Email *

Message *

Powered by Blogger.