EMERGENCY: Two Windows Zero-Days Under Active Attack — One Hits Nearly Every Version
A pair of zero-day vulnerabilities in Microsoft Windows are being actively exploited in the wild. One bug impacts a wide range of builds across Windows 11/10, Windows Server (2012–2022), and legacy editions still operating in factories and branch offices. If your fleet spans the US, EU, UK, AU, or India, treat this as a Code Red incident for both CISO and IT Operations.
Why trust CyberDudeBivash?
- Executive-first risk translation from exploit notes to business continuity, SLA, and revenue impact.
- Guidance aligned to CISA KEV, NIST CSF, ENISA/NIS2, NCSC (UK), ACSC (AU), and CERT-In (India).
- Hands-on Defender/KQL, PowerShell, and Intune/GPO checklists for rapid mitigation.
TL;DR
- What: Two Windows zero-days; one provides privilege escalation / code execution with broad version coverage, the other enables initial access or sandbox escape.
- Impact: Workstations, VDI, RDS hosts, jump boxes, Domain Controllers, and OT/ICS HMIs running Windows variants.
- Active exploitation: Confirmed in the wild. Assume targeted phishing + endpoint post-exploitation frameworks.
- Action now: Enable vendor mitigations, deploy latest updates to canaries and Tier-0, push emergency rings, and monitor IOC/behavior below.
Who’s at Highest Risk?
- Enterprises with mixed vintages (Windows 7/8.1/2012 still around for shop-floor apps or medical/lab devices).
- RDP/WinRM/SMB exposed to the internet, or partners connected via VPN without strict device posture.
- Manufacturing, Healthcare, BFSI, Government, Retail, SaaS in US/EU/UK/AU/IN.
Likely Attack Chains
- Phish → Scripted dropper (JS/HTA/ISO) → LOLBin execution (
mshta
,rundll32
,powershell
) → Zero-day for privilege escalation → C2 + credential dumping. - Browser/Document exploit → sandbox escape → UAC bypass / token theft → AD discovery → lateral movement via SMB/RDP.
Immediate Actions (0–24 Hours)
- Tier-0 first: Domain Controllers, PKI, management servers, hypervisors, and jump hosts — patch ahead of user endpoints.
- Block risky LOLBins: SRP/AppLocker/WDAC deny
mshta.exe
,wscript.exe
,rundll32.exe
for non-admin users. - EDR hardening: Turn on cloud-delivered protection, tamper protection, and ASR rules (Office macros, script abuse, LSASS credential theft).
- Macro/Attachment controls: Strip
.js
,.hta
,.iso
,.lnk
at the secure email gateway; enable SafeLinks/SafeAttachments. - Internet-exposed Windows: Put behind ZTNA or VPN with device health; geo/IP throttle; remove direct RDP/SMB exposure.
Rapid Patch Rings (Intune / SCCM)
- Ring 0 (Canary) — 25–50 diverse endpoints and one non-prod DC.
- Ring 1 (Tier-0) — DCs, management plane, bastions/jump boxes.
- Ring 2 (Critical Biz Apps) — VDI, RDS, file/print, app servers.
- Ring 3 (General Fleet) — All remaining workstations and kiosks.
Detection: Microsoft Defender KQL
DeviceProcessEvents | where Timestamp > ago(7d) | where InitiatingProcessParentFileName in~ ("winword.exe","excel.exe","outlook.exe","acrord32.exe","chrome.exe","msedge.exe") | where FileName in~ ("powershell.exe","pwsh.exe","wscript.exe","cscript.exe","mshta.exe","rundll32.exe","regsvr32.exe") | project Timestamp, DeviceName, InitiatingProcessParentFileName, FileName, ProcessCommandLine, InitiatingProcessCommandLine, InitiatingProcessSHA1
DeviceImageLoadEvents | where Timestamp > ago(7d) | where InitiatingProcessFileName in~ ("lsass.exe","winlogon.exe","explorer.exe") | where FileName has_any ("dbghelp.dll","comsvcs.dll","samlib.dll") // LSASS scraping hallmarks | summarize dcount(DeviceName) by FileName
PowerShell: Patch/Build Audit (Run as Admin)
Get-ComputerInfo | Select-Object CsName, WindowsVersion, OsName, OsArchitecture, OsBuildNumber Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 10 Source, Description, HotFixID, InstalledOn
Hardening Checklist (GPO/Intune)
- Credential Guard + LSA Protection on Windows 10/11 and Server 2019+.
- Disable SMBv1; restrict NTLM; enable LDAP signing and channel binding.
- Exploit Protection profiles (DEP/ASLR/CFG) — enforce for Office and PDF readers.
- Attack Surface Reduction rules: Block Office from creating child processes; Block credential stealing from LSASS; Block executable content from email/webmail.
OT/Factory & Healthcare Notes
For ICS/HMI or medical/lab devices pinned to older Windows builds in India’s Make-in-India plants, EU factories, UK NHS, AU health networks: apply virtual patching (network IPS/WAF), tighten allow-lists, and schedule maintenance windows with vendor validation before reboot.
Compliance & Reporting
- US (CISA/NIST CSF): DE.AE-2 anomalies, PR.IP-12 vulnerability management, RS.MI-1 mitigation.
- EU (NIS2/ENISA): Timely patching and incident handling for essential entities; supplier oversight.
- UK (NCSC CAF): D2 protective tech, M2 detection & log retention.
- AU (ACSC Essential Eight): Patch applications/OS, macro controls, application control, harden MS Office.
- India (CERT-In): 180-day log retention; notifiable incidents within mandated timelines.
C-Suite Brief
Situation: Two Windows zero-days are being exploited. One impacts most supported versions; the other is used for initial access.
Risk: Endpoint takeover, lateral movement to AD, data theft, ransomware downtime.
Action: Emergency patch rings in flight; Tier-0 prioritized; EDR and ASR tightened; external exposures reduced.
Business impact: Patching/reboots during approved windows; user prompts possible due to increased controls.
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Editor’s Picks — Windows Zero-Day Response Stack
Behavioral detections, ASR, tamper protection Patch Orchestration (Intune/SCCM add-on)
Ringed deployments, reboot coordination Secure Email Gateway + Sandbox
Detonate HTA/ISO/LNK, stop phish initial access Privileged Access Management
Vault, JIT, session isolation for Tier-0
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Windows Security · Zero Day · CISO Briefing · Incident Response
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