CVE-2020-17441
📋 TL;DR
This vulnerability in picoTCP allows attackers to trigger an out-of-bounds read during ICMPv6 checksum calculation by sending malformed IPv6 packets with incorrect payload length fields. This can lead to denial-of-service crashes or potential information disclosure from memory. It affects systems using picoTCP 1.7.0 for network communication.
💻 Affected Systems
- picoTCP
📦 What is this software?
Mplab Harmony by Microchip
Picotcp by Altran
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, though information disclosure is more likely given the CWE-125 classification.
Likely Case
Denial-of-service through application crashes or information disclosure via memory leaks.
If Mitigated
Minimal impact if proper network segmentation and input validation are implemented.
🎯 Exploit Status
Exploitation requires sending specially crafted IPv6 packets to vulnerable systems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.7.1 or later
Vendor Advisory: https://github.com/tass-belgium/picotcp
Restart Required: Yes
Instructions:
1. Update picoTCP to version 1.7.1 or later. 2. Recompile any applications using picoTCP. 3. Restart affected services or systems.
🔧 Temporary Workarounds
Disable IPv6
linuxDisable IPv6 functionality in picoTCP or at the system level
sysctl -w net.ipv6.conf.all.disable_ipv6=1
sysctl -w net.ipv6.conf.default.disable_ipv6=1
Network filtering
linuxBlock ICMPv6 traffic at network boundaries
iptables -A INPUT -p ipv6-icmp -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Deploy intrusion detection systems to monitor for malformed IPv6 packets
🔍 How to Verify
Check if Vulnerable:
Check picoTCP version in source code or compiled binaries. Version 1.7.0 is vulnerable.Check Version:
grep -r "PICO_VERSION" in source code or check build configurationVerify Fix Applied:
Verify picoTCP version is 1.7.1 or later and test with IPv6 traffic.📡 Detection & Monitoring
Log Indicators:
- Application crashes
- Memory access violation errors
- Unexpected process termination
Network Indicators:
- Malformed IPv6 packets with incorrect payload length
- ICMPv6 checksum errors
SIEM Query:
source="network" AND (proto="ipv6" AND (payload_length_mismatch OR icmpv6_checksum_error))