CVE-2017-3208
📋 TL;DR
This vulnerability allows attackers to exploit XML External Entity (XXE) processing in WebORB for Java's AMF3 deserializer, potentially leading to sensitive data exposure, denial of service, or server-side request forgery. It affects systems using WebORB for Java version 5.1.1.0 with the vulnerable Java AMF3 implementation.
💻 Affected Systems
- WebORB for Java by Midnight Coders
📦 What is this software?
Weborb For Java by Themidnightcoders
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution, complete server compromise, and data exfiltration via XXE attacks embedded in AMF3 messages.
Likely Case
Sensitive file disclosure (e.g., /etc/passwd), denial of service via entity expansion attacks, or internal network probing via SSRF.
If Mitigated
Limited impact if XML parsing is disabled or external entity resolution is blocked at network/application layers.
🎯 Exploit Status
Exploitation requires sending crafted AMF3 messages with embedded XXE payloads; public proof-of-concept demonstrates file disclosure.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.1.1.1 or later
Vendor Advisory: http://www.themidnightcoders.com/
Restart Required: Yes
Instructions:
1. Upgrade WebORB for Java to version 5.1.1.1 or later. 2. Replace the vulnerable AMF3 deserializer library. 3. Restart the application server.
🔧 Temporary Workarounds
Disable XXE Processing
allConfigure XML parsers to disable external entity resolution in the AMF3 deserializer.
Set XML parser properties: FEATURE_SECURE_PROCESSING = true, DISALLOW_DOCTYPE_DECL = true
Input Validation Filter
allImplement a filter to reject AMF3 messages containing XML DOCTYPE declarations or external entity references.
🧯 If You Can't Patch
- Block or filter incoming AMF3 traffic at network perimeter (e.g., WAF rules to detect XXE patterns).
- Isolate affected systems in segmented network zones to limit lateral movement if compromised.
🔍 How to Verify
Check if Vulnerable:
Check WebORB version in application configuration or library files; if version is 5.1.1.0, it is vulnerable.Check Version:
grep -r 'weborb' /path/to/webapp/ | grep -i versionVerify Fix Applied:
Verify WebORB version is 5.1.1.1 or later and test with a benign XXE payload to confirm rejection.📡 Detection & Monitoring
Log Indicators:
- Unusual AMF3 deserialization errors
- XML parsing exceptions with external entity references
- Increased server load from malformed requests
Network Indicators:
- AMF3 traffic containing XML DOCTYPE or ENTITY declarations
- Outbound requests from server to internal resources triggered by incoming AMF3 messages
SIEM Query:
source="*weborb*" AND (message="*XXE*" OR message="*DOCTYPE*" OR message="*ENTITY*")🔗 References
- http://www.securityfocus.com/bid/97384
- http://www.securityweek.com/flaws-java-amf-libraries-allow-remote-code-execution
- https://codewhitesec.blogspot.com/2017/04/amf.html
- https://www.kb.cert.org/vuls/id/307983
- http://www.securityfocus.com/bid/97384
- http://www.securityweek.com/flaws-java-amf-libraries-allow-remote-code-execution
- https://codewhitesec.blogspot.com/2017/04/amf.html
- https://www.kb.cert.org/vuls/id/307983
