CVE-2021-38383
📋 TL;DR
CVE-2021-38383 is a use-after-free vulnerability in OwnTone's net_bind() function that allows attackers to execute arbitrary code or cause denial of service. This affects OwnTone (owntone-server) users running versions through 28.1. Attackers can exploit this remotely without authentication.
💻 Affected Systems
- OwnTone (owntone-server)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Denial of service causing service crashes and disruption of media streaming functionality.
If Mitigated
Limited impact if network access is restricted and exploit attempts are blocked by security controls.
🎯 Exploit Status
Use-after-free vulnerabilities typically require specific memory manipulation knowledge but are often weaponized once details are public.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after commit 246d8ae0cef27377e5dfe9ee3ad87e864d6b6266
Vendor Advisory: https://github.com/owntone/owntone-server/commit/246d8ae0cef27377e5dfe9ee3ad87e864d6b6266
Restart Required: Yes
Instructions:
1. Update OwnTone to version after commit 246d8ae0cef27377e5dfe9ee3ad87e864d6b6266. 2. Restart the OwnTone service. 3. Verify the service is running correctly.
🔧 Temporary Workarounds
Network Restriction
linuxRestrict network access to OwnTone service to trusted IPs only
iptables -A INPUT -p tcp --dport 3689 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 3689 -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation and firewall rules to limit access to OwnTone service
- Deploy intrusion detection/prevention systems to monitor for exploit attempts
🔍 How to Verify
Check if Vulnerable:
Check OwnTone version: owntone --version or check installed package versionCheck Version:
owntone --version || dpkg -l | grep owntone || rpm -qa | grep owntoneVerify Fix Applied:
Verify version is newer than 28.1 or includes commit 246d8ae0cef27377e5dfe9ee3ad87e864d6b6266📡 Detection & Monitoring
Log Indicators:
- Unexpected service crashes
- Memory access violation errors in system logs
- Unusual network connections to port 3689
Network Indicators:
- Suspicious traffic patterns to OwnTone port (default 3689)
- Multiple connection attempts with malformed packets
SIEM Query:
source="owntone.log" AND ("segmentation fault" OR "use-after-free" OR "memory corruption")