CVE-2023-43615
📋 TL;DR
This CVE describes a buffer overflow vulnerability in Mbed TLS versions 2.x before 2.28.5 and 3.x before 3.5.0. Attackers could exploit this to execute arbitrary code or cause denial of service. Any system using vulnerable Mbed TLS versions for TLS/SSL operations is affected.
💻 Affected Systems
- Mbed TLS
📦 What is this software?
Fedora by Fedoraproject
Fedora by Fedoraproject
Fedora by Fedoraproject
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Denial of service crashes affecting TLS/SSL services, potentially disrupting secure communications.
If Mitigated
Limited impact with proper network segmentation, minimal privileges, and exploit mitigations like ASLR.
🎯 Exploit Status
Buffer overflow vulnerabilities typically require specific conditions to exploit, but CWE-120 suggests classic buffer overflow patterns that could be leveraged.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.28.5 for 2.x branch, 3.5.0 for 3.x branch
Vendor Advisory: https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2023-10-1/
Restart Required: Yes
Instructions:
1. Identify all systems using Mbed TLS. 2. Update to Mbed TLS 2.28.5 or 3.5.0. 3. Recompile applications if using embedded libraries. 4. Restart affected services. 5. Test functionality after update.
🔧 Temporary Workarounds
Network segmentation and access controls
allRestrict network access to services using Mbed TLS to minimize attack surface.
Disable vulnerable functionality if possible
allIf specific Mbed TLS features are not needed, disable them to reduce exposure.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Deploy additional security controls like WAFs or intrusion prevention systems
🔍 How to Verify
Check if Vulnerable:
Check Mbed TLS version in use: ldd on binaries or check library versions. Vulnerable if version is 2.x < 2.28.5 or 3.x < 3.5.0.Check Version:
For Linux: ldd /path/to/binary | grep mbedtls or check package manager. For embedded systems: check build configuration.Verify Fix Applied:
Confirm Mbed TLS version is 2.28.5 or higher for 2.x, or 3.5.0 or higher for 3.x.📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes of services using TLS/SSL
- Memory access violation errors in application logs
Network Indicators:
- Unusual TLS handshake patterns or malformed packets to TLS ports
SIEM Query:
Example: 'process_crash AND (process_name:contains_tls OR process_name:contains_ssl)'🔗 References
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BDSHAANRULB57GVS5B3DZHXL5KCC7OWQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GGRB5MO2KUJKYPMGXMIZH2WRH6QR5UZS/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/O7SB7L6A56QZALDTOZ6O4X7PTC4I647R/
- https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2023-10-1/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BDSHAANRULB57GVS5B3DZHXL5KCC7OWQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GGRB5MO2KUJKYPMGXMIZH2WRH6QR5UZS/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/O7SB7L6A56QZALDTOZ6O4X7PTC4I647R/
- https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2023-10-1/
