CVE-2020-17445
📋 TL;DR
This vulnerability in picoTCP 1.7.0 allows attackers to cause an out-of-bounds read when processing IPv6 destination options due to insufficient length validation. This can lead to denial-of-service conditions in systems using this TCP/IP stack. Affected systems include embedded devices, IoT devices, and industrial control systems that use picoTCP.
💻 Affected Systems
- picoTCP
📦 What is this software?
Picotcp by Altran
⚠️ Risk & Real-World Impact
Worst Case
Complete system crash or reboot leading to sustained denial-of-service, potentially allowing further exploitation if memory corruption leads to code execution.
Likely Case
Denial-of-service causing device/system instability or crashes when processing malicious IPv6 packets.
If Mitigated
Limited impact with proper network segmentation and filtering, potentially causing temporary service disruption.
🎯 Exploit Status
Exploitation requires sending crafted IPv6 packets to vulnerable systems. No authentication required.
🛠️ 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 library to version 1.7.1 or later. 2. Recompile applications using the library. 3. Restart affected systems/services.
🔧 Temporary Workarounds
Disable IPv6
linuxDisable IPv6 functionality if not required
sysctl -w net.ipv6.conf.all.disable_ipv6=1
sysctl -w net.ipv6.conf.default.disable_ipv6=1
Network Filtering
linuxBlock IPv6 destination option packets at network perimeter
iptables -A INPUT -p ipv6 --destination-options -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Deploy network intrusion prevention systems to detect and block malicious IPv6 packets
🔍 How to Verify
Check if Vulnerable:
Check picoTCP library version in use. If version is 1.7.0, system is vulnerable.Check Version:
Check application/library documentation or build configuration for picoTCP versionVerify Fix Applied:
Verify picoTCP library version is 1.7.1 or later after update.📡 Detection & Monitoring
Log Indicators:
- System crashes
- Unexpected reboots
- Network stack errors
Network Indicators:
- Malformed IPv6 packets with destination options
- Unusual IPv6 traffic to embedded devices
SIEM Query:
source="network_firewall" dest_port=* proto=ipv6 dest_options=*