CVE-2024-52920
📋 TL;DR
Bitcoin Core versions before 0.20.0 contain a vulnerability where remote attackers can send specially crafted GETDATA messages that cause the software to enter an infinite loop, leading to denial of service. This affects all Bitcoin Core nodes running vulnerable versions that accept incoming peer connections. The vulnerability allows attackers to consume 100% CPU resources on affected nodes.
💻 Affected Systems
- Bitcoin Core
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service where Bitcoin Core becomes unresponsive, requiring manual restart and potentially causing transaction processing delays and network synchronization issues.
Likely Case
CPU exhaustion leading to degraded performance, slow block processing, and potential node disconnection from the Bitcoin network.
If Mitigated
Minimal impact if patched or if nodes are behind firewalls that block malicious peer connections.
🎯 Exploit Status
Exploitation requires network access to Bitcoin Core's P2P port (default 8333). The vulnerability is in the message parsing logic and can be triggered by any peer.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.20.0 and later
Vendor Advisory: https://bitcoincore.org/en/2024/07/03/disclose-getdata-cpu/
Restart Required: Yes
Instructions:
1. Stop Bitcoin Core service. 2. Backup wallet.dat and configuration files. 3. Download Bitcoin Core 0.20.0 or later from bitcoincore.org. 4. Install the new version. 5. Restart Bitcoin Core service.
🔧 Temporary Workarounds
Firewall Restriction
linuxBlock incoming connections to Bitcoin Core P2P port from untrusted sources
iptables -A INPUT -p tcp --dport 8333 -j DROP
ufw deny 8333/tcp
Connection Limiting
allReduce maximum connections to minimize attack surface
Add 'maxconnections=8' to bitcoin.conf
🧯 If You Can't Patch
- Implement strict firewall rules to only allow Bitcoin Core connections from trusted peers
- Monitor CPU usage and restart Bitcoin Core if infinite loop is detected
🔍 How to Verify
Check if Vulnerable:
Check Bitcoin Core version with 'bitcoin-cli getnetworkinfo' and verify version is below 0.20.0Check Version:
bitcoin-cli getnetworkinfo | grep versionVerify Fix Applied:
Confirm version is 0.20.0 or higher and monitor for abnormal CPU usage patterns📡 Detection & Monitoring
Log Indicators:
- High CPU usage alerts
- Repeated GETDATA messages in debug.log
- Node disconnection events
Network Indicators:
- Unusual GETDATA message patterns
- High volume of malformed P2P messages
SIEM Query:
source="bitcoin.log" AND "GETDATA" AND ("error" OR "malformed")