Why attackers love PowerShell (high-level)

• Native & trusted: Ships with Windows, blends into admin ops (ATT&CK: T1059.001).

• Memory-heavy workflows: Can operate file-less; fewer on-disk artefacts.

• Remote automation: WinRM/PSRemoting can pivot laterally if poorly governed.

• Evasion surface: Obfuscation, encoded commands, and attempts to bypass AMSI.

Tactical tells of malicious use (what to hunt)

• Long Base64-encoded command lines (-enc, -e, unusual 400–4000 char blobs).

• Non-interactive launches from office apps, browsers, scripting hosts, or archives.

• PowerShell v2 engine usage (deprecated; often targeted).

• AMSI errors in logs or script-block failures that coincide with process spawns.

• Bursty remote sessions (WinRM) to many hosts from one workstation.

Turn on the lights (logging to enable)

• Script Block Logging (Event ID 4104) and Module Logging (ID 4103).

• PowerShell Transcription (captures raw input/output).

• Process creation (Windows 4688) + command-line auditing.

• Sysmon (Events 1, 3, 7, 11, 13, 15, 22) for process/DLL/network/file and AMSI.

• PowerShell v2 disablement (Group Policy), and prefer PowerShell 7 for admins.

Keep logs for at least 30–90 days; forward to SIEM with host labels (tier, owner).

Block what you can (preventive controls)

• WDAC / AppLocker: Allow-list signed admin tools and approved scripts only.

• ASR Rules (Defender): Block Office from creating child processes; block obfuscated scripts; block credential theft.

• Constrained Language Mode: Apply via WDAC/AppLocker for non-admins.

• JEA (Just Enough Administration): Role-scoped endpoints limiting cmdlets/params.

• Remove local admin where not required; enforce MFA on remote management.

Quick SIEM hunts (safe, detection-only)

• Encoded command usage

  • Idea: Look for powershell.exe/pwsh.exe with -enc or -encodedcommand, especially when parent is Office, browser, Teams, PDF reader, archive tool.

• Abnormal parent/child chains

  • Idea: Office/Acrobat/7zip/WinRAR → PowerShell → new process.

• PowerShell v2 invocations

  • Idea: Image path contains WindowsPowerShell\v1.0 plus -Version 2 or DLL load of System.Management.Automation v2.

• AMSI failures

  • Idea: Events indicating AMSI init or scan errors correlated with blocked events.

If you want, I can drop ready-to-paste KQL/Sigma detection snippets tailored to your SIEM—just say which platform (Defender, Sentinel, Splunk, Elastic).

Incident response playbook (high-level)

1. Triage: Isolate host; snapshot volatile data (netstat, running procs, PS history).

2. Scope: Hunt for the same command line on other hosts; check WinRM logs.

3. Contain: Revoke tokens/sessions; disable compromised accounts; block C2 IOCs.

4. Eradicate: Remove persistence (scheduled tasks, WMI, Run keys, services).

5. Recover: Reimage if integrity is uncertain; restore from clean backups.

6. Lessons: Patch gaps (logging, allow-listing, rights model), purple-team test.

Hardening checklist (copy/pin)

• Disable PowerShell v2; mandate PowerShell 7 for admins.

• Enable 4103/4104 logging + Transcription to a central share.

• Deploy WDAC/AppLocker policies (publisher rules).

• Turn on ASR rules and Network Protection.

• Configure JEA for routine admin tasks.

• Require MFA for PSRemoting; restrict by Just-In-Time access.

• Baseline what good looks like (approved scripts, management stations).

• Quarterly purple-team exercises against these detections.

Executive takeaways

• PowerShell is not the enemy—unchecked freedom is.

• Visibility + allow-listing + least privilege beat signature cat-and-mouse.

• Treat administrative tooling like production code: governance, review, logging.

CyberDudeBivash CTA (safe & on-brand)

• Defense Playbooks & Detection Packs: cyberdudebivash.com/latest-tools-services-offered-by-cyberdudebivash/

• Daily Threat Intel: cyberbivash.blogspot.com

•  Need bespoke PowerShell hardening & SIEM content? I’ll ship it.

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