Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Dissecting Logons

Guy Leech
November 18, 2020

Dissecting Logons

Tools and techniques for examining what happens/happened during a Windows user logon to aid troubleshooting slowness and other problems.

Given, with demos, at the Romanian Citrix User Group meeting, November 2020

Guy Leech

November 18, 2020
Tweet

More Decks by Guy Leech

Other Decks in Technology

Transcript

  1. DETERMINING WHAT HAS RUN & WHY • SysInternals Process Monitor

    • Windows Performance Recorder & Analyser • Event logs • 300+ event logs • Process Creation & Termination Auditing (plus cmdline) • Gpresult • Scheduled Tasks • Logon scripts • Users • Group & Local policy • … and don’t forget device drivers, especially file system filters, & services
  2. SYSINTERNALS PROCESS MONITOR • Capture start/stop on single user OS

    • Sethc / utilman hijack (crude & AV products now stopping) • Remote PowerShell session (elegant) • SysInternals psexec (old fashioned but not WinRM dependent) • Process Tree • Look at creation times, command lines, parent processes & durations • Filter out unwanted & noise, e.g. other sessions (but not session zero) • But have to know in advance that you want to monitor a logon
  3. EVENT LOGS • There are more than 4 event logs!

    Yes, really • 495 on my Win10 2004 laptop with 168 containing events • Search them all over the logon period • Look for "interesting" entries/clues/errors • PowerShell to the rescue (again) • Cross reference to Process Start/Stop – enable creation & termination auditing • Great for post mortems (unless you always have tracing enabled )
  4. CONTROLUP LOGON ANALYSIS SCRIPT • Doesn’t need ControlUp to run

    • Download from script library • Needs logon and process creation/termination auditing in place + cmdline • Script can do this for you locally or set via GPO • Just need to pass domain\user parameter for simplest use • Outputs phases including group policy, logon script & printer mappings • Also now shows Fslogix, Ivanti Environment Manager & VMware AppVolumes & DEM stages
  5. WINDOWS PERFORMANCE RECORDER & ANALYSER • Standard in Windows 10

    • But need Windows 10 SDK/ADK full version for on/off traces • Although can copy folder once installed for recording & analysis • wpr.exe -start CPU -start DiskIO -start FileIO -start Registry -start Network -start Minifilter -onoffscenario boot -onoffresultspath c:\temp - onoffproblemdescription SlowBootSlowLogon -numiterations 1 • Or use the GUI • Stops on logon or use "wpr –stop <trace.etl>" via PowerShell Enter-PSSession, etc • Can be slow to create trace afterwards which can be GB in size • Analyser is a beast – data overload – expert users only 6
  6. OTHER USEFUL THINGS TO LOOK AT • GPSvcDebugLevel • SysInternals

    AutoRuns – what runs at logon that we don't need including ActiveSetup • Base/Default Profile • 3rd party log files e.g. FSlogix , VMware Cloud Volumes, Citrix WEM, Ivanti • Security software/Anti Virus – especially exclusions • User profile persistence (e.g. “Roman” profiles, UPM, Ivanti EM, etc.) • AppSetup value in Winlogon reg key (e.g. usrlogon.cmd) • Appinit_dlls • Local & hypervisor performance counters & network/storage load • Persistent image bloat – e.g. GPO cache, temp folders • Driver installation files in %systemroot%\inf\setupapi.dev.log & setupapi.app.log • The internet – many articles about logon optimisation e.g. @james______________rankin 7
  7. PARTING THOUGHTS …. • Is it already fast enough? •

    Is it worth the effort/cost to try & make it any faster? • Is it consistent? • Do you really need to do everything at logon for every user every time? • Maintainability • Documentation • Future Proofing • Logon analysis is available as a bespoke consultancy service from @guyrleech