CVE-2020-22283
📋 TL;DR
This CVE describes a buffer overflow vulnerability in lwIP's ICMPv6 packet handling that allows attackers to read sensitive memory contents via crafted packets. It affects systems using vulnerable versions of the lwIP networking stack, particularly embedded devices and IoT systems. The vulnerability enables information disclosure but not code execution.
💻 Affected Systems
- lwIP (lightweight IP)
📦 What is this software?
Lwip by Lwip Project
⚠️ Risk & Real-World Impact
Worst Case
Attackers could read sensitive memory contents including passwords, keys, or other application data from the device's memory space.
Likely Case
Information disclosure of network stack memory, potentially revealing internal state or adjacent memory contents.
If Mitigated
With proper network segmentation and filtering, impact is limited to information disclosure within the affected network segment.
🎯 Exploit Status
Exploitation requires sending crafted ICMPv6 packets to vulnerable systems. No public exploit code identified in references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in lwIP git repository (specific commit not specified)
Vendor Advisory: https://savannah.nongnu.org/bugs/index.php?58553
Restart Required: Yes
Instructions:
1. Update lwIP to patched version from official repository. 2. Recompile applications using lwIP. 3. Restart affected services or devices.
🔧 Temporary Workarounds
Disable ICMPv6
linuxDisable ICMPv6 processing if not required for network functionality
sysctl -w net.ipv6.icmp.echo_ignore_all=1
iptables -A INPUT -p ipv6-icmp -j DROP
Filter ICMPv6 traffic
linuxBlock incoming ICMPv6 packets at network perimeter
iptables -A INPUT -p ipv6-icmp --icmpv6-type echo-request -j DROP
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable devices
- Deploy network-based intrusion detection to monitor for ICMPv6 anomalies
🔍 How to Verify
Check if Vulnerable:
Check lwIP version in use and compare against patched versions. For embedded devices, check firmware version against vendor advisories.Check Version:
Check application documentation or vendor information for lwIP version. For source builds: grep LWIP_VERSION in lwipopts.h or similar configuration files.Verify Fix Applied:
Verify lwIP version has been updated to include the fix for CVE-2020-22283. Test with ICMPv6 packets to ensure no memory disclosure occurs.📡 Detection & Monitoring
Log Indicators:
- Unusual ICMPv6 traffic patterns
- System crashes or instability in network stack
Network Indicators:
- Malformed ICMPv6 packets targeting vulnerable systems
- Unusual ICMPv6 response patterns
SIEM Query:
source="network" AND protocol="ICMPv6" AND (payload_size>normal OR malformed_packet=true)