Patch-Window Pressure:
The 48-Hour Sprint

1️⃣ Block RSC endpoints at the firewall (if app is internal-only)

iptables -A INPUT -p tcp --dport 3000 -s <internal-subnet> -j ACCEPT

Effect: External scans can't reach your app (buys you days)

2️⃣ Rate-limit POST requests to /_next/data/ (if WAF is available)

Cloudflare: 10 requests/min per IP

Effect: Mass exploitation campaigns fail (attackers move to easier targets)

3️⃣ Enable verbose logging for RSC endpoints (free, takes 2 min)

# Next.js: Set DEBUG=* in .env

Effect: You'll see exploitation attempts in real-time (early warning)

1️⃣ Block RAR file extraction at email gateway

Office 365: Transport Rule → Block attachments with .rar extension
Gmail: Admin Console → Attachments → Add ".rar" to blocked list

⏱️ Time: 3 minutes | Effect: Eliminates delivery vector entirely

2️⃣ Enable Startup folder monitoring (Sysmon)

# Sysmon config (add to <RuleGroup name="FileCreate">)
<FileCreate onmatch="include">
  <TargetFilename condition="contains">\Start Menu\Programs\Startup\</TargetFilename>
</FileCreate>

⏱️ Time: 5 minutes | Effect: Real-time alerts on Startup folder writes

3️⃣ Audit existing Startup folders (hunt for compromise NOW)

Get-ChildItem "C:\Users\*\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\" -Recurse | Select-Object FullName, CreationTime, LastWriteTime

⏱️ Time: 2 minutes | Effect: Identifies if you're already compromised

🔴 ACTIVELY EXPLOITED:

• CVE-2025-62221 — Windows Cloud Files Mini Filter Driver EoP (CVSS 7.8)
• Use-after-free → local privilege escalation to SYSTEM
• Any local user → SYSTEM privileges → full host compromise

🟡 PUBLICLY DISCLOSED (Not Yet Exploited):

• CVE-2025-64671 — GitHub Copilot for JetBrains RCE (CVSS 7.3)
• Malicious project files → commands execute with developer privileges
• CVE-2025-54100 — PowerShell RCE via Invoke-WebRequest (CVSS 7.8)
• Scripts downloading web content → malicious code execution

🔴 CRITICAL RCE FLAWS:

• CVE-2025-62562 — Microsoft Outlook RCE (CVSS 9.0) ← Highest CVSS this month
• CVE-2025-62554/62557 — Microsoft Office RCE (CVSS 8.8)

CVE-2025-62221 (Cloud Files EoP):

CVE-2025-54100 (PowerShell RCE):

1️⃣ Restrict local admin rights (mitigates CVE-2025-62221)

# Remove users from local Administrators group
net localgroup Administrators /delete DOMAIN\User

⏱️ Time: 10 minutes (GPO) | Effect: Limits EoP impact

2️⃣ Audit PowerShell scripts for Invoke-WebRequest

Get-ChildItem -Path "C:\Scripts" -Recurse -Filter "*.ps1" | Select-String -Pattern "Invoke-WebRequest|curl" | Select-Object Path, LineNumber, Line

⏱️ Time: 5 minutes | Effect: Identifies vulnerable scripts

3️⃣ Enable Office Protected View

Group Policy: User Configuration → Administrative Templates → Microsoft Office → Security Settings → Trust Center → Protected View
Enable: "Protected View for files originating from the Internet"

⏱️ Time: 5 minutes (GPO) | Effect: Blocks Office RCE auto-execution

Confirmed Vulnerable Products:

Custom .NET Applications:

1️⃣ Block file:// scheme at WAF

# ModSecurity rule (example)
SecRule ARGS "@contains file://" \
  "id:1001,phase:2,deny,status:403,msg:'Blocked file:// in WSDL URL'"

⏱️ Time: 5 minutes | Effect: Prevents malicious WSDL with file:// handlers

2️⃣ Enable file integrity monitoring for web directories

# Monitor for new .aspx/.ashx files
Get-ChildItem -Path "C:\inetpub\wwwroot" -Recurse -Filter "*.aspx" | Where-Object {$_.CreationTime -gt (Get-Date).AddDays(-7)}

⏱️ Time: 10 minutes | Effect: Alerts when new web shells appear

3️⃣ Restrict IIS AppPool write permissions

# Remove write access from web root
icacls "C:\inetpub\wwwroot" /remove "IIS APPPOOL\YourAppPool" /T

⏱️ Time: 5 minutes | Effect: Prevents web shell creation even if exploited