CVE-2019-1335
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected systems by exploiting a memory corruption flaw in Microsoft Edge's Chakra JavaScript engine. Attackers could compromise user systems by tricking victims into visiting malicious websites. This affects users running vulnerable versions of Microsoft Edge on Windows 10.
💻 Affected Systems
- Microsoft Edge
📦 What is this software?
Chakracore by Microsoft
Edge by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install programs, view/change/delete data, or create new accounts with full user rights.
Likely Case
Attackers gain user-level access to execute code, steal sensitive data, or install malware through drive-by attacks.
If Mitigated
Limited impact with proper browser sandboxing and security controls, potentially contained to browser process.
🎯 Exploit Status
Exploitation requires memory corruption techniques but no authentication. No public exploit code was released according to Microsoft's advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: October 2019 security update for Windows 10
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1335
Restart Required: Yes
Instructions:
1. Open Windows Update settings. 2. Click 'Check for updates'. 3. Install October 2019 security update KB4520008 or later. 4. Restart computer when prompted.
🔧 Temporary Workarounds
Disable JavaScript
windowsDisable JavaScript in Microsoft Edge to prevent exploitation of the Chakra engine vulnerability
Not applicable - use Edge settings: edge://settings/content/javascript
Use Application Guard
windowsEnable Microsoft Defender Application Guard to isolate Edge browsing sessions
Enable-WindowsOptionalFeature -Online -FeatureName Windows-Defender-ApplicationGuard
🧯 If You Can't Patch
- Switch to Chromium-based Microsoft Edge which is not affected by this vulnerability
- Use alternative browsers like Chrome or Firefox until patching is possible
🔍 How to Verify
Check if Vulnerable:
Check Edge version: Open Edge > Settings > About Microsoft Edge. If version is before 44.18362.387.0 (October 2019 update), system is vulnerable.Check Version:
wmic datafile where name="C:\\Program Files (x86)\\Microsoft\\Edge\\Application\\msedge.exe" get versionVerify Fix Applied:
Verify Windows Update installed KB4520008 or later: Open Settings > Update & Security > View update history.📡 Detection & Monitoring
Log Indicators:
- Edge crash logs with exception codes like 0xC0000005 (ACCESS_VIOLATION)
- Unexpected Edge process termination
- Suspicious JavaScript execution patterns
Network Indicators:
- Connections to known malicious domains from Edge process
- Unusual outbound traffic patterns after visiting websites
SIEM Query:
EventID=1000 OR EventID=1001 AND SourceName='Application Error' AND ProcessName='MicrosoftEdge.exe' AND ExceptionCode='0xc0000005'