CVE-2020-24027
📋 TL;DR
CVE-2020-24027 is a critical buffer overflow vulnerability in liblivemedia's RTSP server component. When processing a specially crafted RTSP PLAY command with absolute time seeking, attackers can execute arbitrary code or crash the service. This affects any system using vulnerable versions of liblivemedia for RTSP streaming.
💻 Affected Systems
- Live Networks liblivemedia
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise, allowing attackers to take complete control of affected servers.
Likely Case
Service disruption through denial of service (crash) or limited code execution in constrained environments.
If Mitigated
Minimal impact if proper network segmentation and least privilege principles are implemented.
🎯 Exploit Status
The vulnerability is in protocol handling and requires no authentication. Public details make exploitation straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 20200625
Vendor Advisory: http://lists.live555.com/pipermail/live-devel/2020-July/021662.html
Restart Required: Yes
Instructions:
1. Download latest liblivemedia from live555.com. 2. Replace vulnerable library files. 3. Recompile any dependent applications. 4. Restart affected services.
🔧 Temporary Workarounds
Disable absolute time seeking
allConfigure RTSP server to reject PLAY commands with absolute time parameters
Modify RTSP server configuration to disable 'absolute' time seeking mode
Network filtering
allBlock or filter RTSP traffic at network boundaries
iptables -A INPUT -p tcp --dport 554 -j DROP
firewall-cmd --permanent --add-port=554/tcp
netsh advfirewall firewall add rule name="Block RTSP" dir=in action=block protocol=TCP localport=554
🧯 If You Can't Patch
- Isolate RTSP servers in dedicated network segments with strict access controls
- Implement application layer firewalls to inspect and filter RTSP traffic
🔍 How to Verify
Check if Vulnerable:
Check liblivemedia version: strings /path/to/liblivemedia.so | grep '20200625' or similarCheck Version:
strings $(ldconfig -p | grep liblivemedia | head -1 | awk '{print $4}') | grep 'LIVE555'Verify Fix Applied:
Verify version is newer than 20200625 and test RTSP PLAY commands with absolute time parameters📡 Detection & Monitoring
Log Indicators:
- RTSP PLAY commands with unusually long absolute time parameters
- Service crashes or abnormal termination
Network Indicators:
- RTSP traffic with malformed PLAY commands
- Unexpected connections to RTSP port 554
SIEM Query:
source="rtsp_server" AND (message="*PLAY*absolute*" OR message="*buffer overflow*")