CVE-2021-33945
📋 TL;DR
A stack buffer overflow vulnerability in RICOH printer firmware allows attackers to cause Denial of Service (DoS) by sending crafted data to the wpa_supplicant.conf file. This affects multiple RICOH SP series printer models running vulnerable firmware versions. The high CVSS score indicates critical severity with potential for complete system disruption.
💻 Affected Systems
- RICOH SP 320DN
- SP 325DNw
- SP 320SN
- SP 320SFN
- SP 325SNw
- SP 325SFNw
- SP 330SN
- Aficio SP 3500SF
- SP 221S
- SP 220SNw
- SP 221SNw
- SP 221SF
- SP 220SFNw
- SP 221SFNw
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete printer system crash requiring physical reboot, potential for remote code execution if exploit chains with other vulnerabilities, and persistent DoS affecting all printing services.
Likely Case
Printer becomes unresponsive to network requests, requiring manual power cycle to restore functionality, disrupting printing services for connected users.
If Mitigated
Limited to isolated printer disruption if network segmentation prevents external access, with quick restoration via power cycle.
🎯 Exploit Status
Public GitHub repository contains exploit details, making exploitation straightforward for attackers with network access to vulnerable printers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware versions after v1.06
Vendor Advisory: https://www.ricoh.com/info/2022/0228_1/
Restart Required: Yes
Instructions:
1. Download latest firmware from RICOH support portal. 2. Upload firmware to printer via web interface. 3. Apply update. 4. Reboot printer to complete installation.
🔧 Temporary Workarounds
Network Segmentation
allIsolate printers on separate VLAN with strict firewall rules to prevent external access.
Disable Unused Services
allTurn off unnecessary network services on printer to reduce attack surface.
🧯 If You Can't Patch
- Implement strict network access controls to limit printer access to authorized IPs only.
- Monitor printer logs for unusual connection attempts or service disruptions.
🔍 How to Verify
Check if Vulnerable:
Check printer firmware version via web interface or display panel. If version is exactly v1.06, system is vulnerable.Check Version:
Check via printer web interface at http://[printer-ip]/web/guest/en/websys/webArch/getStatus.cgi or physical display menu.Verify Fix Applied:
Confirm firmware version is updated to version after v1.06 via printer web interface or display.📡 Detection & Monitoring
Log Indicators:
- Multiple failed connection attempts to printer services
- Printer service crashes or restarts
- Unusual network traffic to printer port 80/443
Network Indicators:
- Unusual payloads sent to printer web interface
- Traffic patterns matching known exploit signatures
SIEM Query:
source="printer_logs" AND (event="service_crash" OR event="buffer_overflow")