CVE-2021-44530
📋 TL;DR
This is the Log4Shell vulnerability (CVE-2021-44228) affecting UniFi Network software. It allows remote code execution via JNDI injection in Log4j, enabling attackers to take full control of affected systems. Organizations running UniFi Network Version 6.5.53 or earlier are vulnerable.
💻 Affected Systems
- UniFi Network Application
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install malware, steal data, pivot to other systems, and maintain persistent access.
Likely Case
Remote code execution leading to cryptocurrency mining, ransomware deployment, or data exfiltration.
If Mitigated
Limited impact with proper network segmentation, egress filtering, and security controls preventing successful exploitation.
🎯 Exploit Status
Widely exploited in the wild with numerous public proof-of-concept exploits available. Attack requires no authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 6.5.54 and later
Vendor Advisory: https://community.ui.com/releases/Security-Advisory-Bulletin-023-023/808a1db0-5f8e-4b91-9097-9822f3f90207
Restart Required: Yes
Instructions:
1. Download UniFi Network Version 6.5.54 or later from UI.com. 2. Stop the UniFi Network service. 3. Install the updated version. 4. Restart the service.
🔧 Temporary Workarounds
Log4j JVM Parameter Mitigation
allSet Log4j system property to disable JNDI lookups
Add '-Dlog4j2.formatMsgNoLookups=true' to JVM startup parameters
Remove JndiLookup Class
linuxRemove vulnerable Log4j class file from installation
find /usr/lib/unifi -name "*log4j*.jar" -exec zip -q -d {} org/apache/logging/log4j/core/lookup/JndiLookup.class \;
🧯 If You Can't Patch
- Block outbound LDAP and RMI traffic from UniFi systems at network perimeter
- Implement strict network segmentation to isolate UniFi systems from critical assets
🔍 How to Verify
Check if Vulnerable:
Check UniFi Network version via web interface or command: 'java -jar /usr/lib/unifi/lib/log4j-core-*.jar' to check Log4j versionCheck Version:
grep -i version /usr/lib/unifi/system.properties 2>/dev/null || check web interfaceVerify Fix Applied:
Verify version is 6.5.54 or later in UniFi web interface under Settings > System📡 Detection & Monitoring
Log Indicators:
- ${jndi:ldap://
- ${jndi:rmi://
- ${jndi:dns:// in application logs
Network Indicators:
- Outbound LDAP/RMI connections from UniFi systems to unknown external IPs
SIEM Query:
source="unifi" AND "${jndi:"