CVE-2024-35426
📋 TL;DR
CVE-2024-35426 is a critical stack buffer overflow vulnerability in vmir's WebAssembly parser that allows remote code execution. Attackers can exploit this by providing malicious WebAssembly modules to trigger the overflow in the init_local_vars function. This affects all systems running vulnerable versions of vmir that process untrusted WebAssembly content.
💻 Affected Systems
- vmir
📦 What is this software?
Vmir by Lonelycoder
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with remote code execution as the vmir process user, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Remote code execution leading to service disruption, data exfiltration, or installation of backdoors on affected systems.
If Mitigated
Denial of service through application crash if exploit attempts are blocked or fail.
🎯 Exploit Status
Proof-of-concept available in GitHub issue. Exploitation requires sending a malicious WebAssembly module to the vulnerable parser.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in references, but fix should be in versions after e8117
Vendor Advisory: https://github.com/andoma/vmir/issues/24
Restart Required: Yes
Instructions:
1. Check current vmir version
2. Update to latest version from official repository
3. Restart all vmir services
4. Verify the fix is applied
🔧 Temporary Workarounds
Disable WebAssembly Processing
allTemporarily disable vmir's WebAssembly parsing functionality if not required
# Configuration depends on vmir deployment method
# Consult vmir documentation for disabling WASM parsing
Network Segmentation
linuxRestrict network access to vmir services to trusted sources only
# Example using iptables for Linux
iptables -A INPUT -p tcp --dport [vmir-port] -s [trusted-ip] -j ACCEPT
iptables -A INPUT -p tcp --dport [vmir-port] -j DROP
🧯 If You Can't Patch
- Implement strict input validation for WebAssembly modules before passing to vmir
- Deploy vmir in isolated containers with minimal privileges and network access
🔍 How to Verify
Check if Vulnerable:
Check if vmir version is e8117 or earlier by examining version output or build metadataCheck Version:
vmir --version or check build/version information in application outputVerify Fix Applied:
Test with known malicious WebAssembly module from PoC to ensure it no longer triggers overflow📡 Detection & Monitoring
Log Indicators:
- Segmentation fault or crash logs from vmir process
- Unusually large WebAssembly module processing attempts
- Stack overflow error messages in application logs
Network Indicators:
- Unusual network traffic patterns to vmir WebAssembly endpoints
- Large WebAssembly module transfers to vmir services
SIEM Query:
source="vmir" AND ("segmentation fault" OR "stack overflow" OR "SIGSEGV")