CVE-2020-4450
📋 TL;DR
CVE-2020-4450 is a critical remote code execution vulnerability in IBM WebSphere Application Server that allows attackers to execute arbitrary code by sending specially crafted serialized objects. This affects WebSphere Application Server 8.5 and 9.0 traditional editions. Organizations running these versions are at risk of complete system compromise.
💻 Affected Systems
- IBM WebSphere Application Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with administrative privileges, data theft, lateral movement, and persistent backdoor installation.
Likely Case
Remote code execution leading to application compromise, data exfiltration, and potential ransomware deployment.
If Mitigated
Limited impact if proper network segmentation, least privilege, and serialization filters are implemented.
🎯 Exploit Status
Exploits leverage Java deserialization vulnerabilities. Multiple public proof-of-concepts exist.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply Interim Fix PH30777 for 8.5 and PH30778 for 9.0, or upgrade to 8.5.5.19/9.0.5.6
Vendor Advisory: https://www.ibm.com/support/pages/node/6220294
Restart Required: Yes
Instructions:
1. Download appropriate interim fix from IBM Fix Central. 2. Stop WebSphere Application Server. 3. Apply the fix using IBM Installation Manager. 4. Restart the server. 5. Verify fix application.
🔧 Temporary Workarounds
Disable IIOP Protocol
allBlocks the attack vector by disabling IIOP protocol which is required for exploitation
Navigate to Administrative Console > Servers > Server Types > WebSphere application servers > server_name > Ports > Uncheck 'BOOTSTRAP_ADDRESS' and 'SAS_SSL_SERVERAUTH_LISTENER_ADDRESS'
Apply Serialization Filter
allImplement Java serialization filter to block malicious deserialization
Add to JVM arguments: -Dcom.ibm.websphere.serialfilter=true -Dcom.ibm.websphere.serialfilter.properties=serialfilter.properties
🧯 If You Can't Patch
- Implement strict network segmentation to isolate WebSphere servers from untrusted networks
- Deploy web application firewall with Java deserialization protection rules
🔍 How to Verify
Check if Vulnerable:
Check WebSphere version via Administrative Console or run: $WAS_HOME/bin/versionInfo.shCheck Version:
$WAS_HOME/bin/versionInfo.shVerify Fix Applied:
Verify interim fix installation via Installation Manager or check version is 8.5.5.19/9.0.5.6 or higher📡 Detection & Monitoring
Log Indicators:
- Unusual IIOP connection attempts
- Java deserialization errors in SystemOut.log
- Unexpected process creation
Network Indicators:
- IIOP traffic to WebSphere ports (typically 2809)
- Unusual outbound connections from WebSphere servers
SIEM Query:
source="WebSphere" AND ("deserialization" OR "IIOP" OR "RemoteMethodInvocation")🔗 References
- https://exchange.xforce.ibmcloud.com/vulnerabilities/181231
- https://www.ibm.com/support/pages/node/6220294
- https://www.zerodayinitiative.com/advisories/ZDI-20-689/
- https://exchange.xforce.ibmcloud.com/vulnerabilities/181231
- https://www.ibm.com/support/pages/node/6220294
- https://www.zerodayinitiative.com/advisories/ZDI-20-689/
