CVE-2023-38180
📋 TL;DR
This CVE describes a denial of service vulnerability in .NET and Visual Studio that allows attackers to crash affected applications by sending specially crafted requests. It affects systems running vulnerable versions of .NET Framework, .NET Core, and Visual Studio. The vulnerability can be exploited remotely without authentication.
💻 Affected Systems
- .NET Framework
- .NET Core
- .NET 5.0
- .NET 6.0
- .NET 7.0
- Visual Studio 2022
- Visual Studio 2019
📦 What is this software?
.net by Microsoft
.net by Microsoft
Asp.net Core by Microsoft
Fedora by Fedoraproject
Fedora by Fedoraproject
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption of affected applications, leading to business downtime and potential data loss if applications handle critical operations.
Likely Case
Application crashes causing temporary service unavailability, requiring manual restart of affected services.
If Mitigated
Minimal impact with proper network segmentation and monitoring; services automatically restart but may experience brief downtime.
🎯 Exploit Status
Microsoft rates this as 'Exploitation More Likely' in their advisory; the CISA catalog inclusion suggests active exploitation is occurring or expected.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Varies by product: .NET 7.0.10+, .NET 6.0.21+, and specific updates for older versions as per Microsoft advisory
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-38180
Restart Required: Yes
Instructions:
1. Identify affected .NET/Visual Studio installations. 2. Apply Microsoft security updates via Windows Update or download from Microsoft Update Catalog. 3. Restart affected systems and applications. 4. For Linux systems, update via package manager (apt-get update && apt-get upgrade dotnet-sdk-7.0 etc.).
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to affected applications to trusted sources only
Rate Limiting
allImplement rate limiting on application endpoints to reduce impact of DoS attempts
🧯 If You Can't Patch
- Implement strict network access controls and firewall rules to limit exposure
- Deploy web application firewalls (WAF) with DoS protection rules enabled
🔍 How to Verify
Check if Vulnerable:
Check installed .NET version with 'dotnet --info' or Windows Registry for .NET Framework versions; compare against patched versions in Microsoft advisory.Check Version:
dotnet --info (for .NET Core/5/6/7) or check registry at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP (for .NET Framework)Verify Fix Applied:
Verify version numbers match or exceed patched versions: .NET 7.0.10+, .NET 6.0.21+, etc. Check Windows Update history for security updates.📡 Detection & Monitoring
Log Indicators:
- Unexpected application crashes
- High memory/CPU usage spikes
- Multiple failed requests from single sources
- Stack traces indicating unhandled exceptions in .NET runtime
Network Indicators:
- High volume of requests to .NET application endpoints
- Unusual traffic patterns from external sources
- Requests with malformed headers or parameters
SIEM Query:
source="application_logs" AND ("unhandled exception" OR "crash" OR "terminated") AND process="dotnet" OR process="w3wp"🔗 References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-38180
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CL2L4WE5QRT7WEXANYXSKSU43APC5N2V/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NWVZFKTLNMNKPZ755EMRYIA6GHFOWGKY/
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-38180
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-38180
