CVE-2023-32571
📋 TL;DR
CVE-2023-32571 is a remote code execution vulnerability in Dynamic LINQ libraries where untrusted input to methods like Where, Select, and OrderBy can be parsed to execute arbitrary commands. This affects applications using vulnerable versions of System.Linq.Dynamic.Core. Attackers can achieve full system compromise through this injection vulnerability.
💻 Affected Systems
- System.Linq.Dynamic.Core
📦 What is this software?
Linq by Dynamic Linq
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with attacker executing arbitrary code as the application's user, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Remote code execution leading to application compromise, data exfiltration, and potential privilege escalation.
If Mitigated
Limited impact with proper input validation and sanitization, potentially reduced to denial of service or information disclosure.
🎯 Exploit Status
Exploitation requires user input to reach vulnerable Dynamic LINQ methods. Public proof-of-concept demonstrates code execution.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.3.0 and later
Vendor Advisory: https://github.com/zzzprojects/System.Linq.Dynamic.Core
Restart Required: Yes
Instructions:
1. Update System.Linq.Dynamic.Core NuGet package to version 1.3.0 or later. 2. Rebuild and redeploy affected applications. 3. Test application functionality after update.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation and sanitization for all user inputs passed to Dynamic LINQ methods.
Restrict Dynamic LINQ Usage
allDisable or restrict usage of Dynamic LINQ methods in production environments where possible.
🧯 If You Can't Patch
- Implement Web Application Firewall (WAF) rules to block suspicious Dynamic LINQ query patterns
- Isolate vulnerable applications in network segments with strict egress filtering
🔍 How to Verify
Check if Vulnerable:
Check project dependencies for System.Linq.Dynamic.Core version 1.0.7.10 through 1.2.25. Review code for Dynamic LINQ method usage with user input.Check Version:
For .NET projects: check packages.config or .csproj file for System.Linq.Dynamic.Core versionVerify Fix Applied:
Verify System.Linq.Dynamic.Core package version is 1.3.0 or later in project dependencies. Test application with known malicious inputs.📡 Detection & Monitoring
Log Indicators:
- Unusual long strings in query parameters
- Suspicious characters like semicolons, parentheses, or quotes in LINQ queries
- Application errors related to Dynamic LINQ parsing
Network Indicators:
- Unusual outbound connections from application server
- Large data exfiltration patterns
SIEM Query:
source="application_logs" AND ("Dynamic.Linq" OR "System.Linq.Dynamic") AND (error OR exception)🔗 References
- https://github.com/zzzprojects/System.Linq.Dynamic.Core
- https://research.nccgroup.com/2023/06/13/dynamic-linq-injection-remote-code-execution-vulnerability-cve-2023-32571/
- https://github.com/zzzprojects/System.Linq.Dynamic.Core
- https://research.nccgroup.com/2023/06/13/dynamic-linq-injection-remote-code-execution-vulnerability-cve-2023-32571/
