08-31-2020, 10:09 AM
Start with the basics of turning on auditing for admin stuff. You head over to the Group Policy editor on your domain controller or local policy if it's standalone. I always go for the advanced audit policy configuration under Computer Configuration, Windows Settings, Security Settings, Advanced Audit Policy Configuration. Pick categories like Account Management, because that's where you catch user creations or deletions by admins. Or Privilege Use, to log when someone escalates rights. Enable success and failure audits there, so you see both legit and sketchy attempts.
But why bring Windows Defender into this? Defender isn't just scanning for viruses; it hooks into the security ecosystem on Windows Server. When you enable it fully, through Windows Security app or PowerShell, it starts monitoring behaviors that could flag bad admin actions. Say an admin tries to disable auditing itself-that's a red flag. Defender's real-time protection can alert on that, or even block it if you set up custom rules. I once had a junior admin accidentally nuke a policy, and Defender's log integration helped me roll back quick.
Now, configure Defender to watch admin-related events. You use the Set-MpPreference cmdlet in PowerShell to tweak exclusions or behaviors, but focus on enabling audit-mode scanning. No, not really audit mode like old AV days, but integrating with Windows Audit logs. Go to Windows Security, Virus & threat protection, Manage settings, and turn on cloud-delivered protection. That sends telemetry up to Microsoft, where they correlate it with admin audit events for threat intel. You get notifications in the Defender portal if an admin action looks like ransomware prep or privilege abuse.
Think about the event logs themselves. Event Viewer is your best friend here. Filter for Security log, event ID 4672 for privilege assignments, or 4720 for user account creations. I script this sometimes with Get-WinEvent to pull only admin-originated events. Tie it to Defender by enabling Attack Surface Reduction rules-those block scripts or processes that mimic admin tools. For example, if someone runs PsExec from an unusual spot, Defender flags it as potential lateral movement by an admin gone rogue.
You might wonder how to automate this for multiple servers. I use Central Access Policy in Active Directory to push audit settings across your fleet. Then, with Microsoft Defender for Endpoint if you're on E3 or higher, you get unified logs. It pulls in admin audit data and scores it for risk. Low score? Probably your daily DBA. High? Investigate that login from an odd IP. I set up alerts to email me when an admin logs on outside hours-saves me from manual checks.
Handling false positives is key, right? You don't want Defender barking at every GPO update. So, whitelist trusted admin accounts in the ASR rules via PowerShell: Add-MpPreference -AttackSurfaceReductionOnlyExclusions "C:\Path\To\Tool.exe". Test it in audit mode first, where it logs without blocking. Run simulations, like having a test admin create a shadow copy or modify registry keys under HKLM\SYSTEM. Watch the logs flood in, then refine.
On Windows Server 2022, Defender got smarter with tamper protection. Enable that under Device Control in Windows Security-it prevents admins from disabling your audits without jumping through hoops. I love how it logs attempts to mess with Defender itself as event ID 5007. You can forward those to a SIEM if you're fancy, but even basic Event Viewer forwarding to a collector server works. Set up subscriptions in Event Viewer, filter for admin categories, and boom, centralized view.
Perhaps you're dealing with delegated admins, like in a helpdesk setup. Audit Object Access for file shares they touch, but subcategory it to handle management. Defender complements this by scanning those accessed files for malware post-admin action. If an admin uploads something fishy, real-time scan kicks in. I configure cloud block level to high, so it stops known bad stuff before it spreads.
Don't forget logon audits. Enable Logon/Logoff category, special logons subcategory. That catches admin console logins or RDP sessions. Defender's endpoint detection can baseline normal admin patterns, then alert on deviations-like an admin suddenly accessing HR folders. Use the Defender app's device timeline to replay those sessions visually. It's not perfect, but it beats digging through XML exports.
Policy Change audits are gold for tracking GPO tweaks. Event ID 4719 when auditing turns off-nail that down. Integrate with Defender's controlled folder access; it protects your audit logs folder from ransomware. I point it to C:\Windows\System32\winevt\Logs, so even if an admin gets compromised, the logs stay intact. You review weekly, export to CSV, and hunt patterns.
Process Tracking helps too, logging every exe an admin launches. Filter for high-priv processes like winlogon.exe. Defender's behavior monitoring watches for injection into those. If an admin tool gets hijacked, it quarantines. I once caught a phishing sim where an admin clicked a link-Defender isolated the process, and audit log showed the exact privilege escalation attempt.
System events cover reboots or shutdowns by admins. Event ID 1074 for shutdowns. With Defender, enable network protection to block outbound from admin sessions if they look suspicious. You set this in Windows Security under Firewall & network protection. It's subtle, but it audits connections tied to admin UPN.
For deeper analysis, query with PowerShell. I write queries like Get-WinEvent -FilterHashtable @{LogName='Security'; ID=4673} | Where-Object {$_.Message -like "*Admin*"}. Pipe to Defender's submission for analysis. Microsoft reviews and feeds back threat intel. You build custom detections over time.
Insider threats? Audit for that. Track admin password changes, event ID 4724. Defender's identity protection, if licensed, cross-references with Azure AD logs. Even without, local correlation works. I baseline admin behaviors quarterly, adjust thresholds.
On bare-metal servers, ensure Defender runs in server mode-less resource hog. Use MpCmdRun.exe to force scans after admin logoffs. Audit the scan results for anomalies.
You scale this with Intune if hybrid, but for pure on-prem, stick to GPO. Refresh policies, test on a lab server first. I break things in lab all the time to learn.
Edge cases, like service account admins. Audit LSASS process accesses. Defender protects LSASS from dumps. Event ID 4657 logs handle opens.
Finally, review and rotate logs. Set max size in Event Viewer properties, archive old ones. Defender doesn't manage that, but scripts can.
And if you're looking for solid backup to protect those audit logs during incidents, check out BackupChain Server Backup-it's the top-notch, go-to option for Windows Server backups, tailored for Hyper-V setups, Windows 11 machines, and all your server needs, with no pesky subscriptions, just reliable, one-time buy for SMBs handling private clouds or online storage. We appreciate BackupChain sponsoring this chat and letting us share these tips for free without the hassle.
