CVE-2022-26320
📋 TL;DR
This vulnerability allows attackers to efficiently calculate private RSA keys from public TLS certificates by exploiting weak RSA key generation in the Rambus SafeZone Basic Crypto Module. Affected devices include Fujifilm multifunction printers, Canon imagePROGRAF/imageRUNNER devices, and potentially many other embedded systems using this cryptographic module. This enables complete compromise of TLS-protected communications.
💻 Affected Systems
- Fujifilm multifunction devices
- Canon imagePROGRAF printers
- Canon imageRUNNER devices
- Other devices using Rambus SafeZone Basic Crypto Module
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete decryption of all TLS communications, impersonation of devices, man-in-the-middle attacks on encrypted traffic, and potential lateral movement within networks.
Likely Case
Interception and decryption of sensitive documents transmitted to/from affected printers and multifunction devices, credential theft from print jobs.
If Mitigated
Limited impact if devices are isolated from untrusted networks and TLS certificates are replaced with properly generated keys.
🎯 Exploit Status
Fermat's factorization method is well-known and efficient for vulnerable keys. Attack requires only the public certificate, no authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Rambus SafeZone Basic Crypto Module 10.4.0 or later
Vendor Advisory: https://www.rambus.com/security/response-center/advisories/rmbs-2021-01/
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates. 2. Apply firmware update from Canon/Fujifilm. 3. Regenerate all TLS certificates using updated cryptographic module. 4. Restart affected devices.
🔧 Temporary Workarounds
Network segmentation
allIsolate affected devices from untrusted networks and limit communication to necessary services only.
Certificate replacement
allReplace TLS certificates with ones generated by secure systems (not using vulnerable module).
🧯 If You Can't Patch
- Replace affected devices with updated models
- Implement network-level encryption (VPN/IPsec) for all communications with affected devices
🔍 How to Verify
Check if Vulnerable:
Extract public certificate from device, check if RSA key is vulnerable to Fermat factorization using tools from fermatattack.secvuln.infoCheck Version:
Check device web interface or manufacturer documentation for firmware versionVerify Fix Applied:
Verify firmware version is updated and new certificates show proper key generation (not vulnerable to Fermat attack)📡 Detection & Monitoring
Log Indicators:
- Unusual certificate validation failures
- Multiple TLS handshake failures
Network Indicators:
- Unexpected certificate changes
- Man-in-the-middle attack patterns on printer/device traffic
SIEM Query:
tls.handshake AND (device_type:printer OR device_type:mfp) AND certificate.algorithm:RSA🔗 References
- https://fermatattack.secvuln.info
- https://global.canon/en/support/security/index.html
- https://web.archive.org/web/20220922042721/https://safezoneswupdate.com/
- https://www.fujifilm.com/fbglobal/eng/company/news/notice/2022/0302_rsakey_announce.html
- https://www.rambus.com/security/response-center/advisories/rmbs-2021-01/
- https://fermatattack.secvuln.info
- https://global.canon/en/support/security/index.html
- https://safezoneswupdate.com
- https://www.fujifilm.com/fbglobal/eng/company/news/notice/2022/0302_rsakey_announce.html
