CVE-2022-50932
📋 TL;DR
Kyocera Command Center RX ECOSYS M2035dn has a directory traversal vulnerability that allows unauthenticated attackers to read sensitive system files like /etc/passwd and /etc/shadow by manipulating file paths. This affects organizations using the vulnerable Kyocera multifunction printer software, potentially exposing credential information and system configuration.
💻 Affected Systems
- Kyocera Command Center RX ECOSYS M2035dn
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain full system access by extracting password hashes from /etc/shadow and cracking them, then using those credentials to compromise the entire system or network.
Likely Case
Attackers read sensitive system files containing user information, configuration details, and potentially credential hashes, leading to information disclosure and possible credential theft.
If Mitigated
Limited information disclosure with no direct path to system compromise if proper network segmentation and access controls are in place.
🎯 Exploit Status
Exploit requires simple HTTP requests with directory traversal sequences and null-byte injection. Public exploit code available on Exploit-DB (ID 50738).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not explicitly stated in public sources - check Kyocera security advisory
Vendor Advisory: https://www.kyoceradocumentsolutions.com/asia/en/products/business-application/command-center-rx.html
Restart Required: Yes
Instructions:
1. Check Kyocera security advisory for latest firmware. 2. Download firmware update from Kyocera support portal. 3. Apply firmware update through printer web interface or local interface. 4. Restart printer to apply changes.
🔧 Temporary Workarounds
Network Access Restriction
linuxRestrict network access to the printer's web interface to only trusted management networks
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_NETWORK -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s TRUSTED_NETWORK -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Disable Web Interface
allTemporarily disable the web interface if not required for operations
Access printer settings via local interface -> Network Settings -> Disable HTTP/HTTPS services
🧯 If You Can't Patch
- Isolate the printer on a separate VLAN with strict firewall rules preventing external and unnecessary internal access
- Implement network monitoring for directory traversal patterns in HTTP requests to the printer
🔍 How to Verify
Check if Vulnerable:
Send HTTP GET request to http://[printer-ip]/js/../../../../etc/passwd%00.jpg and check if /etc/passwd contents are returnedCheck Version:
Check firmware version via printer web interface: Settings -> Device Information -> Firmware VersionVerify Fix Applied:
Attempt the same exploit request after patching - should return error or empty response instead of file contents📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing '/js/../../' patterns
- Requests with null-byte (%00) in URL
- Unusual file access patterns from external IPs
Network Indicators:
- HTTP traffic to printer on port 80/443 with directory traversal sequences
- Multiple failed attempts followed by successful file disclosure
SIEM Query:
source="printer_logs" AND (url="*js/../*" OR url="*%00*")🔗 References
- https://www.exploit-db.com/exploits/50738
- https://www.kyoceradocumentsolutions.com/asia/en/products/business-application/command-center-rx.html
- https://www.vulncheck.com/advisories/kyocera-command-center-rx-ecosys-mdn-directory-traversal-file-disclosure-unauthenticated
- https://www.exploit-db.com/exploits/50738
