CVE-2023-30362
📋 TL;DR
This CVE describes a buffer overflow vulnerability in the coap_send function of libcoap library versions up to 4.3.1-103-g52cfd56. Attackers can exploit this by sending malformed Protocol Data Units (PDUs) to potentially read sensitive information from memory. Any system using vulnerable versions of libcoap for Constrained Application Protocol (CoAP) communication is affected.
💻 Affected Systems
- libcoap library
📦 What is this software?
Libcoap by Libcoap
⚠️ Risk & Real-World Impact
Worst Case
Information disclosure leading to exposure of sensitive data like encryption keys, credentials, or other memory contents, potentially enabling further attacks.
Likely Case
Partial memory disclosure that could reveal application data or system information useful for reconnaissance.
If Mitigated
No impact if patched or if network controls prevent malicious CoAP traffic.
🎯 Exploit Status
Exploitation requires crafting specific malformed CoAP PDUs to trigger buffer overflow.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.3.1-120-ge242200 and later
Vendor Advisory: https://github.com/obgm/libcoap/issues/1063
Restart Required: Yes
Instructions:
1. Update libcoap to version 4.3.1-120-ge242200 or later. 2. Recompile any applications using libcoap. 3. Restart affected services.
🔧 Temporary Workarounds
Network filtering
allBlock or filter CoAP traffic from untrusted sources at network perimeter.
Input validation
allImplement additional input validation for CoAP PDUs before passing to coap_send.
🧯 If You Can't Patch
- Isolate vulnerable systems in segmented network zones with strict access controls.
- Implement network monitoring for anomalous CoAP traffic patterns.
🔍 How to Verify
Check if Vulnerable:
Check libcoap version: if version <= 4.3.1-103-g52cfd56, system is vulnerable.Check Version:
coap-client --version or check library version in application build configurationVerify Fix Applied:
Verify libcoap version is >= 4.3.1-120-ge242200 and test CoAP functionality.📡 Detection & Monitoring
Log Indicators:
- Application crashes or abnormal termination of CoAP services
- Memory access violation errors in system logs
Network Indicators:
- Unusual CoAP traffic patterns
- Malformed CoAP packets in network captures
SIEM Query:
source="coap" AND (event_type="crash" OR error="buffer" OR error="overflow")