Sami Laiho - Black belt troubleshooting windows 8.1
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Transcript of Sami Laiho - Black belt troubleshooting windows 8.1
Sami Laiho
BlackBelt Troubleshooting Windows 8.1
WHOAMI /ALL (about.me/samilaiho)
• MVP Windows Expert – IT Pro
• SpringBoard Technical Expert Panel member
• Senior Consultant @ Sovelto
• Senior Technical Fellow @ adminize.com
• Twitter: @samilaiho
Windows XP Deep Dive in 2001 by me
Projects
• www.wioski.com – Free replacement for SteadyState
• www.adminize.com – Getting rid of admin rights and provide onetime admin passwords
• www.getabrandnewpassword.com – Free and safe password cracker… I mean changer
• idealinfra.blogspot.com – My blog
You get gpedit.msc and we get…
Housekeeping
• I will give away one free course attendance as promised so leave your business card to participate Winner will be notified afterwards so be sure your card has your email address
• After the session I will stick around for questions and to give away a few T-shirts
Agenda• Baselines and tools for troubleshooting• Error messages• User accounts in troubleshooting• Prelogon diagnostics• Services• Processes and threads• Safemode etc. in Windows 8.1• BSOD in Windows 8.1
BASELINES
Baselines
• I always teach people that the logic in troubleshooting Windows is that there is no logic
• System vs. Boot partition
• System32 vs SysWOW64
• bowser vs browser
• AFD
• Hive
Tools• You always need at least:
• Sysinternals Tools• Sysinternals Suite or http://live.sysinternals.com/
• Debugging Tools• Not so much for debugging but for supporting Sysinternals
Tools• Message analyzer
• Windows 7/8 can capture traces without it with NETSH TRACE• Windows 8.1 is the fisrt to support remote network monitoring
ERROR DESCRIPTIONS
Error descriptions
• To be able to troubleshoot you need good error descriptions especially in Windows 8.1
Error description example
• ”My computer just broke” vs…
Tools for capturing errors
• Net helpmsg & winrm helpmsg
• Copy/Paste dialogs
• Snipping tool
• Windows + Print Screen
• PSR
DEMO – ERROR DESCRIPTIONS IN WINDOWS 8.1
Sami Laiho
USER ACCOUNTS IN TROUBLESHOOTING
SYSTEM vs Admin
• SYSTEM• Has more user privileges than Administrator (even
the Built in one)
• Doesn’t need to worry about policies
• Can see stuff Admin can’t
• Can stop processes Admin can’t
• Has a higher integrity level than Administrator
Mandatory Integrity Control
Mandatory Integrity Control to blaim?
• In Windows Vista+ if you don’t have access to a file and you are sure you should:
• 1. TAKEOWN.exe
• 2. iCacls /SetIntegrityLevel
Running as SYSTEM #1
PSEXEC –SID cmd.exe
Running as SYSTEM #2
DEMO – USING THE SYSTEM-ACCOUNT
Sami Laiho
PRELOGON DIAGNOSTICS
Basic info on logon?
• Event logs are a good start but to do BlackBelt troubleshooting you need:
• SYSTEM-account to diagnose what happens before logon
• Session 0 to diagnose what happens during logon
Building from the ground up - Prelogon
• What happens before logon and how to diagnose it• Slow logons, Startup script
problems, inability to logon…
• Windows has three accounts that never log off• SYSTEM, Local Service and
Network Service
DEMO – PRELOGON DIAGNOSTICS
Sami Laiho
More info on logon?
• If you need more info on your logon don’t forget Autoruns from Sysinternals
More info on logon?• If you need to dig even deeper use Windows
Performance Toolkit
BACKGROUND SERVICES
Background services
• Services not starting/running in Windows 8.1
• Basics: It’s a security issue or something else
• Security• Security log, Secpol.msc, Process Explorer, Process
Monitor
• Something else• Process Monitor
Process Monitor example
What a service can or cannot do
• You have to become a Service
• When you start referring to services as He or She you’re getting the point
Service accounts and user rights
• He/She can use three built in accounts
Service accounts have SIDs
• In Windows 8.1 they have a SID as well
• They become Security Principals
Service accounts have SIDs
DEMO – SERVICE PRIVILEGES
Sami Laiho
PROCESSES AND THREADS
Processes and threads• In Windows a process can’t really do anything
• Task Manager only shows processes…
• Threads can actually do something• Search engines probably know the answer to your question
so the real problem with them is noise• How to get rid of noise?
• Make your searches are more accurate • Make sure you get results from people who have at least a clue on
what they’re doing• Learn to diagnose threads instead of processes
Case – Hanged virtual machine
• VM totally stuck…
• Task manager looks like this
Case – Hanged virtual machine
• Task Manager shows that SYSTEM is causing the problem…
Case – Hanged virtual machine
• Process Explorer shows Threads!
Case – Hanged virtual machine
• Removed the virtual floppy because it was pointing to a nonexisting file
DEMO – PROCESSES VS THREADS
Sami Laiho
SAFEMODE ETC.
How to access boot options in Windows 8.1• Shift-Restart or
Same if you want to goto your UEFI!
Why is a PC working in Safemode?
• Safemode is configured in the registry
Semi-SafeMode – MSCONFIG & AUTORUNS
DEMO – USING AND MANIPULATING SAFE MODE
Sami Laiho
WINDOWS 8.1 BSOD
Changes in BSOD in Windows 8
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\CrashControl
None 0x0
Complete memory dump 0x1
Kernel memory dump 0x2
Small memory dump 0x3
Automatic memory dump
0x7
Make sure you are able to crash when needed!
• http://support.microsoft.com/kb/244139
Basics of BSOD analysis
• Install Debugging tools• Set the systemwide variable _NT_SYMBOL_PATH
to SRV*C:\symbols*http://msdl.microsoft.com/download/symbols• http://support.microsoft.com/kb/311503
• Use WINDBGOpen Crash Dump or DaRT’s Memory Dump Analyzer
Please evaluate the session before you leave
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T-Shirts? Be quick! Remember business cards!!