CVE-2024-30166
📋 TL;DR
A malicious client can exploit a stack buffer over-read vulnerability in Mbed TLS 3.3.0 through 3.5.2 to cause information disclosure or denial of service against TLS 1.3 servers. This affects any system using vulnerable Mbed TLS versions as a TLS server component. The vulnerability is triggered via a specially crafted TLS 1.3 ClientHello message.
💻 Affected Systems
- Mbed TLS
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise leading to sensitive information disclosure, credential theft, and persistent backdoor installation.
Likely Case
Server crash causing denial of service, potentially leaking up to 256 bytes of stack memory containing sensitive data.
If Mitigated
Limited impact with proper network segmentation and intrusion prevention systems blocking malicious traffic.
🎯 Exploit Status
Exploitation requires network access to the TLS server but no authentication. The vulnerability is in the protocol handling code.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.6.0
Vendor Advisory: https://mbed-tls.readthedocs.io/en/latest/tech-updates/security-advisories/
Restart Required: Yes
Instructions:
1. Download Mbed TLS 3.6.0 from official repository. 2. Replace vulnerable version with patched version. 3. Recompile and reinstall if using source. 4. Restart all services using Mbed TLS.
🔧 Temporary Workarounds
Disable TLS 1.3
allTemporarily disable TLS 1.3 support to prevent exploitation while patching
Configure server to only support TLS 1.2 or earlier
Network Filtering
allUse network controls to block malicious ClientHello patterns
Configure WAF/IPS to detect and block abnormal TLS handshakes
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable servers
- Deploy intrusion prevention systems with TLS protocol anomaly detection
🔍 How to Verify
Check if Vulnerable:
Check Mbed TLS version: mbedtls_version_get_string() or check package version. If version is between 3.3.0 and 3.5.2 inclusive, system is vulnerable.Check Version:
mbedtls_version_get_string() or check installed package version via system package managerVerify Fix Applied:
Verify Mbed TLS version is 3.6.0 or higher. Test TLS 1.3 connectivity remains functional.📡 Detection & Monitoring
Log Indicators:
- Unexpected server crashes
- Abnormal TLS handshake failures
- Memory access violation logs
Network Indicators:
- Malformed TLS 1.3 ClientHello packets
- Unusual traffic patterns to TLS ports
SIEM Query:
source="*tls*" AND (event="crash" OR event="access_violation") AND version="3.3.0-3.5.2"