CVE-2016-2783
📋 TL;DR
This vulnerability in Avaya VOSS allows remote attackers to bypass VLAN and I-SIS security controls via specially crafted Ethernet frames, potentially gaining unauthorized network access. It affects Avaya Fabric Connect Virtual Services Platform (VSP) Operating System Software before versions 4.2.3.0 and 5.0.1.0. Organizations using these vulnerable Avaya networking devices are at risk.
💻 Affected Systems
- Avaya Fabric Connect Virtual Services Platform (VSP) Operating System Software (VOSS)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete network compromise allowing attackers to traverse VLAN boundaries, intercept sensitive traffic, and potentially pivot to other systems.
Likely Case
Unauthorized access to restricted network segments, data interception, and potential lateral movement within the network.
If Mitigated
Limited impact if proper network segmentation and monitoring are in place, though VLAN bypass remains possible.
🎯 Exploit Status
Proof-of-concept code is publicly available on Packet Storm. Exploitation requires crafting specific Ethernet frames but doesn't require authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: VOSS 4.2.3.0 and VOSS 5.0.1.0
Vendor Advisory: https://downloads.avaya.com/css/P8/documents/100170866
Restart Required: Yes
Instructions:
1. Download the appropriate firmware update from Avaya support portal. 2. Backup current configuration. 3. Apply the firmware update following Avaya's upgrade procedures. 4. Reboot the device. 5. Verify the new version is running.
🔧 Temporary Workarounds
Network Segmentation Control
allImplement strict network segmentation and access controls to limit exposure of SPB/IS-IS traffic
Traffic Filtering
allUse ACLs to filter suspicious Ethernet frames targeting VLAN/IS-IS indexes
🧯 If You Can't Patch
- Isolate affected devices in separate network segments with strict firewall rules
- Implement network monitoring for unusual SPB/IS-IS traffic patterns and VLAN hopping attempts
🔍 How to Verify
Check if Vulnerable:
Check VOSS version using 'show version' command. If version is below 4.2.3.0 for 4.x or below 5.0.1.0 for 5.x, the device is vulnerable.Check Version:
show versionVerify Fix Applied:
After patching, run 'show version' to confirm version is 4.2.3.0 or higher (for 4.x) or 5.0.1.0 or higher (for 5.x).📡 Detection & Monitoring
Log Indicators:
- Unusual SPB/IS-IS protocol errors
- Unexpected VLAN configuration changes
- Authentication failures from unexpected network segments
Network Indicators:
- Malformed Ethernet frames targeting VLAN/IS-IS indexes
- Traffic crossing VLAN boundaries without proper routing
- Unusual SPB protocol traffic patterns
SIEM Query:
source="avaya-voss" AND (event_type="protocol_error" OR vlan_change="unauthorized")