CVE-2020-0878
📋 TL;DR
This is a memory corruption vulnerability in Microsoft browsers that allows remote code execution. Attackers can exploit it by tricking users into visiting malicious websites, potentially gaining the same privileges as the current user. All users of affected Microsoft browsers are vulnerable.
💻 Affected Systems
- Microsoft Edge
- Internet Explorer
📦 What is this software?
Chakracore by Microsoft
Edge by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with administrative privileges, allowing installation of malware, data theft, and creation of new accounts.
Likely Case
Malware installation or data theft with user-level privileges, potentially leading to credential harvesting or ransomware deployment.
If Mitigated
Limited impact with user-level privileges only, potentially isolated to browser sandbox if properly configured.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website) but no authentication. No public proof-of-concept has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security updates released in March 2020 (specific KB numbers vary by Windows version)
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0878
Restart Required: Yes
Instructions:
1. Apply March 2020 Windows security updates via Windows Update. 2. For enterprise environments, deploy through WSUS or SCCM. 3. Restart systems after update installation.
🔧 Temporary Workarounds
Disable Active Scripting
windowsConfigure Internet Explorer and Edge to disable Active Scripting in Internet and Local intranet security zones
Internet Options > Security tab > Custom Level > Scripting > Active scripting > Disable
Use Enhanced Protected Mode
windowsEnable Enhanced Protected Mode in Internet Explorer to provide additional memory protection
Internet Options > Advanced tab > Security > Enable Enhanced Protected Mode
🧯 If You Can't Patch
- Restrict browser usage to essential personnel only and implement application whitelisting
- Deploy network filtering to block known malicious domains and implement web content filtering
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for March 2020 security updates or verify browser version against patched versionsCheck Version:
wmic qfe list | findstr "KB4540673 KB4540681" (example KB numbers, varies by system)Verify Fix Applied:
Verify March 2020 security updates are installed via Windows Update history or systeminfo command📡 Detection & Monitoring
Log Indicators:
- Unexpected browser crashes, suspicious process creation from browser processes
- Windows Event Logs showing application errors from iexplore.exe or msedge.exe
Network Indicators:
- Outbound connections to suspicious domains following browser usage
- Unusual HTTP traffic patterns from browser processes
SIEM Query:
source="Windows Security" EventCode=4688 AND (NewProcessName="*cmd.exe" OR NewProcessName="*powershell.exe") AND ParentProcessName="*iexplore.exe" OR ParentProcessName="*msedge.exe"