CVE-2020-6072
📋 TL;DR
CVE-2020-6072 is a critical double-free vulnerability in Videolabs libmicrodns 0.1.0 that allows remote code execution via specially crafted mDNS messages. Attackers can exploit this to execute arbitrary code on affected systems. Any system using the vulnerable libmicrodns library for mDNS functionality is at risk.
💻 Affected Systems
- Videolabs libmicrodns
📦 What is this software?
Libmicrodns by Videolabs
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining root/administrator privileges and establishing persistent access.
Likely Case
Service disruption, data exfiltration, or lateral movement within the network.
If Mitigated
Denial of service or application crash if exploit fails.
🎯 Exploit Status
Exploitation requires sending mDNS messages to the vulnerable service, which typically doesn't require authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: libmicrodns 0.2.0 or later
Vendor Advisory: https://github.com/videolabs/libmicrodns/releases
Restart Required: Yes
Instructions:
1. Update libmicrodns to version 0.2.0 or later. 2. Rebuild any applications using libmicrodns. 3. Restart affected services.
🔧 Temporary Workarounds
Network Segmentation
linuxBlock mDNS traffic (port 5353/udp) at network boundaries to prevent external exploitation.
iptables -A INPUT -p udp --dport 5353 -j DROP
Service Disablement
linuxDisable mDNS services if not required for functionality.
systemctl stop avahi-daemon
systemctl disable avahi-daemon
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Deploy intrusion detection systems to monitor for mDNS exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check libmicrodns version: ldd /path/to/application | grep microdns and verify version is 0.1.0Check Version:
pkg-config --modversion libmicrodnsVerify Fix Applied:
Verify libmicrodns version is 0.2.0 or later: pkg-config --modversion libmicrodns📡 Detection & Monitoring
Log Indicators:
- Application crashes
- Memory corruption errors in system logs
- Unusual mDNS traffic patterns
Network Indicators:
- Malformed mDNS packets
- Unusual traffic to/from port 5353/udp
- Exploit pattern detection in network traffic
SIEM Query:
source_port=5353 OR dest_port=5353 AND (protocol=udp) AND (payload_contains="compressed label")🔗 References
- https://security.gentoo.org/glsa/202005-10
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-0995
- https://www.debian.org/security/2020/dsa-4671
- https://security.gentoo.org/glsa/202005-10
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-0995
- https://www.debian.org/security/2020/dsa-4671
