CVE-2020-26508
📋 TL;DR
This vulnerability in Canon Oce ColorWave 3500 printers allows attackers to retrieve stored SMB credentials through the WebTools export feature, bypassing UI restrictions. Attackers can access sensitive authentication data that should be protected. Organizations using affected printer models are at risk.
💻 Affected Systems
- Canon Oce ColorWave 3500
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain access to SMB credentials, potentially compromising entire network shares, deploying ransomware, or conducting lateral movement across the network.
Likely Case
Attackers extract SMB credentials and use them to access shared files and resources on the network, leading to data theft or unauthorized access.
If Mitigated
With proper network segmentation and credential management, impact is limited to isolated printer management network segments.
🎯 Exploit Status
Exploitation requires access to the WebTools interface but no authentication. Simple HTTP requests can trigger credential export.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check with Canon for updated firmware
Vendor Advisory: https://www.canon.com/support/security/
Restart Required: Yes
Instructions:
1. Check Canon security advisory for specific patch version. 2. Download firmware update from Canon support portal. 3. Apply update through printer web interface. 4. Restart printer to complete installation.
🔧 Temporary Workarounds
Disable WebTools Access
linuxBlock external access to WebTools component
iptables -A INPUT -p tcp --dport [WebTools-port] -j DROP
Network Segmentation
allIsolate printer management interface to separate VLAN
🧯 If You Can't Patch
- Remove SMB credentials from printer configuration
- Implement strict firewall rules to limit WebTools access to trusted management hosts only
🔍 How to Verify
Check if Vulnerable:
Access WebTools interface and attempt to trigger export functionality. Check if SMB credentials are exposed in export data.Check Version:
Check printer web interface > System Information > Firmware VersionVerify Fix Applied:
After patching, attempt the same export functionality to confirm credentials are no longer exposed.📡 Detection & Monitoring
Log Indicators:
- Unusual export requests in WebTools logs
- Multiple failed authentication attempts followed by export requests
Network Indicators:
- HTTP requests to WebTools export endpoints from unauthorized IPs
- Unusual SMB connections originating from printer IP
SIEM Query:
source="printer_logs" AND (event="export" OR event="credentials")